2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstbuffer.c: Buffer operations
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Data-passing buffer type
26 * @see_also: #GstPad, #GstMiniObject, #GstMemory, #GstMeta, #GstBufferPool
28 * Buffers are the basic unit of data transfer in GStreamer. They contain the
29 * timing and offset along with other arbitrary metadata that is associated
30 * with the #GstMemory blocks that the buffer contains.
32 * Buffers are usually created with gst_buffer_new(). After a buffer has been
33 * created one will typically allocate memory for it and add it to the buffer.
34 * The following example creates a buffer that can hold a given video frame
35 * with a given width, height and bits per plane.
37 * <title>Creating a buffer for a video frame</title>
41 * gint size, width, height, bpp;
43 * size = width * height * bpp;
44 * buffer = gst_buffer_new ();
45 * memory = gst_allocator_alloc (NULL, size, NULL);
46 * gst_buffer_insert_memory (buffer, -1, memory);
51 * Alternatively, use gst_buffer_new_allocate()
52 * to create a buffer with preallocated data of a given size.
54 * Buffers can contain a list of #GstMemory objects. You can retrieve how many
55 * memory objects with gst_buffer_n_memory() and you can get a pointer
56 * to memory with gst_buffer_peek_memory()
58 * A buffer will usually have timestamps, and a duration, but neither of these
59 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
60 * meaningful value can be given for these, they should be set. The timestamps
61 * and duration are measured in nanoseconds (they are #GstClockTime values).
63 * The buffer DTS refers to the timestamp when the buffer should be decoded and
64 * is usually monotonically increasing. The buffer PTS refers to the timestamp when
65 * the buffer content should be presented to the user and is not always
66 * monotonically increasing.
68 * A buffer can also have one or both of a start and an end offset. These are
69 * media-type specific. For video buffers, the start offset will generally be
70 * the frame number. For audio buffers, it will be the number of samples
71 * produced so far. For compressed data, it could be the byte offset in a
72 * source or destination file. Likewise, the end offset will be the offset of
73 * the end of the buffer. These can only be meaningfully interpreted if you
74 * know the media type of the buffer (the preceeding CAPS event). Either or both
75 * can be set to #GST_BUFFER_OFFSET_NONE.
77 * gst_buffer_ref() is used to increase the refcount of a buffer. This must be
78 * done when you want to keep a handle to the buffer after pushing it to the
79 * next element. The buffer refcount determines the writability of the buffer, a
80 * buffer is only writable when the refcount is exactly 1, i.e. when the caller
81 * has the only reference to the buffer.
83 * To efficiently create a smaller buffer out of an existing one, you can
84 * use gst_buffer_copy_region(). This method tries to share the memory objects
85 * between the two buffers.
87 * If a plug-in wants to modify the buffer data or metadata in-place, it should
88 * first obtain a buffer that is safe to modify by using
89 * gst_buffer_make_writable(). This function is optimized so that a copy will
90 * only be made when it is necessary.
92 * Several flags of the buffer can be set and unset with the
93 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
94 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlag is set.
96 * Buffers can be efficiently merged into a larger buffer with
97 * gst_buffer_append(). Copying of memory will only be done when absolutely
100 * Arbitrary extra metadata can be set on a buffer with gst_buffer_add_meta().
101 * Metadata can be retrieved with gst_buffer_get_meta(). See also #GstMeta
103 * An element should either unref the buffer or push it out on a src pad
104 * using gst_pad_push() (see #GstPad).
106 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
107 * the refcount drops to 0, any memory and metadata pointed to by the buffer is
108 * unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
109 * the pool when the refcount drops to 0.
111 * Last reviewed on 2012-03-28 (0.11.3)
113 #include "gst_private.h"
122 #include "gstbuffer.h"
123 #include "gstbufferpool.h"
125 #include "gstutils.h"
126 #include "gstversion.h"
128 GType _gst_buffer_type = 0;
130 typedef struct _GstMetaItem GstMetaItem;
137 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
139 #define GST_BUFFER_MEM_MAX 16
141 #define GST_BUFFER_SLICE_SIZE(b) (((GstBufferImpl *)(b))->slice_size)
142 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
143 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
144 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
145 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
146 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
154 /* the memory blocks */
156 GstMemory *mem[GST_BUFFER_MEM_MAX];
158 /* memory of the buffer when allocated from 1 chunk */
161 /* FIXME, make metadata allocation more efficient by using part of the
168 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
170 GstMemory *mcur, *mprv;
171 gboolean have_offset = FALSE;
176 for (i = 0; i < len; i++) {
184 /* check if memory is contiguous */
185 if (!gst_memory_is_span (mprv, mcur, &poffs))
192 *parent = mprv->parent;
202 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
204 GstMemory **mem, *result;
206 mem = GST_BUFFER_MEM_ARRAY (buffer);
208 if (G_UNLIKELY (length == 0)) {
210 } else if (G_LIKELY (length == 1)) {
211 result = gst_memory_ref (mem[idx]);
213 GstMemory *parent = NULL;
214 gsize size, poffset = 0;
216 size = gst_buffer_get_size (buffer);
218 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
220 if (GST_MEMORY_IS_NO_SHARE (parent)) {
221 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
222 result = gst_memory_copy (parent, poffset, size);
224 result = gst_memory_share (parent, poffset, size);
227 gsize i, tocopy, left;
228 GstMapInfo sinfo, dinfo;
231 result = gst_allocator_alloc (NULL, size, NULL);
232 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
237 for (i = idx; i < length && left > 0; i++) {
238 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
239 tocopy = MIN (sinfo.size, left);
240 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
241 "memcpy %" G_GSIZE_FORMAT " bytes for merge %p from memory %p",
242 tocopy, result, mem[i]);
243 memcpy (ptr, (guint8 *) sinfo.data, tocopy);
246 gst_memory_unmap (mem[i], &sinfo);
248 gst_memory_unmap (result, &dinfo);
255 _replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
261 GST_LOG ("buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer,
264 /* unref old memory */
265 for (i = idx; i < end; i++)
266 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
269 /* replace with single memory */
270 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
276 g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
277 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
279 GST_BUFFER_MEM_LEN (buffer) = len - length;
283 _memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
285 guint i, len = GST_BUFFER_MEM_LEN (buffer);
287 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
288 /* too many buffer, span them. */
289 /* FIXME, there is room for improvement here: We could only try to merge
290 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
291 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
292 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
294 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
295 /* we now have 1 single spanned buffer */
302 for (i = len; i > idx; i--) {
303 /* move buffers to insert, FIXME, we need to insert first and then merge */
304 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
306 /* and insert the new buffer */
307 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
308 GST_BUFFER_MEM_LEN (buffer) = len + 1;
311 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
314 _priv_gst_buffer_initialize (void)
316 _gst_buffer_type = gst_buffer_get_type ();
320 * gst_buffer_copy_into:
321 * @dest: a destination #GstBuffer
322 * @src: a source #GstBuffer
323 * @flags: flags indicating what metadata fields should be copied.
324 * @offset: offset to copy from
325 * @size: total size to copy. If -1, all data is copied.
327 * Copies the information from @src into @dest.
329 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
330 * the memory from @src will be appended to @dest.
332 * @flags indicate which fields will be copied.
335 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
336 GstBufferCopyFlags flags, gsize offset, gsize size)
340 gboolean region = FALSE;
342 g_return_if_fail (dest != NULL);
343 g_return_if_fail (src != NULL);
345 /* nothing to copy if the buffers are the same */
346 if (G_UNLIKELY (dest == src))
349 g_return_if_fail (gst_buffer_is_writable (dest));
351 bufsize = gst_buffer_get_size (src);
352 g_return_if_fail (bufsize >= offset);
356 size = bufsize - offset;
359 g_return_if_fail (bufsize >= offset + size);
361 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
362 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
365 if (flags & GST_BUFFER_COPY_FLAGS) {
367 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
370 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
372 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
373 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
374 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
375 if (size == bufsize) {
376 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
377 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
380 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
381 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
382 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
383 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
384 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
388 if (flags & GST_BUFFER_COPY_MEMORY) {
390 gsize skip, left, len, i, bsize;
392 len = GST_BUFFER_MEM_LEN (src);
396 /* copy and make regions of the memory */
397 for (i = 0; i < len && left > 0; i++) {
398 mem = GST_BUFFER_MEM_PTR (src, i);
399 bsize = gst_memory_get_sizes (mem, NULL, NULL);
402 /* don't copy buffer */
407 tocopy = MIN (bsize - skip, left);
408 if (GST_MEMORY_IS_NO_SHARE (mem)) {
409 /* no share, always copy then */
410 mem = gst_memory_copy (mem, skip, tocopy);
412 } else if (tocopy < bsize) {
413 /* we need to clip something */
414 mem = gst_memory_share (mem, skip, tocopy);
417 mem = gst_memory_ref (mem);
419 _memory_add (dest, -1, mem);
423 if (flags & GST_BUFFER_COPY_MERGE) {
424 len = GST_BUFFER_MEM_LEN (dest);
425 _replace_memory (dest, len, 0, len, _get_merged_memory (dest, 0, len));
429 if (flags & GST_BUFFER_COPY_META) {
430 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
431 GstMeta *meta = &walk->meta;
432 const GstMetaInfo *info = meta->info;
434 if (info->transform_func) {
435 GstMetaTransformCopy copy_data;
437 copy_data.region = region;
438 copy_data.offset = offset;
439 copy_data.size = size;
441 info->transform_func (dest, meta, src,
442 _gst_meta_transform_copy, ©_data);
449 _gst_buffer_copy (GstBuffer * buffer)
453 g_return_val_if_fail (buffer != NULL, NULL);
455 /* create a fresh new buffer */
456 copy = gst_buffer_new ();
458 /* we simply copy everything from our parent */
459 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
464 /* the default dispose function revives the buffer and returns it to the
465 * pool when there is a pool */
467 _gst_buffer_dispose (GstBuffer * buffer)
471 /* no pool, do free */
472 if ((pool = buffer->pool) == NULL)
475 /* keep the buffer alive */
476 gst_buffer_ref (buffer);
477 /* return the buffer to the pool */
478 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
479 gst_buffer_pool_release_buffer (pool, buffer);
485 _gst_buffer_free (GstBuffer * buffer)
487 GstMetaItem *walk, *next;
491 g_return_if_fail (buffer != NULL);
493 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
496 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
497 GstMeta *meta = &walk->meta;
498 const GstMetaInfo *info = meta->info;
500 /* call free_func if any */
502 info->free_func (meta, buffer);
505 /* and free the slice */
506 g_slice_free1 (ITEM_SIZE (info), walk);
509 /* get the size, when unreffing the memory, we could also unref the buffer
511 msize = GST_BUFFER_SLICE_SIZE (buffer);
513 /* free our memory */
514 len = GST_BUFFER_MEM_LEN (buffer);
515 for (i = 0; i < len; i++)
516 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
518 /* we set msize to 0 when the buffer is part of the memory block */
520 g_slice_free1 (msize, buffer);
522 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
526 gst_buffer_init (GstBufferImpl * buffer, gsize size)
528 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type,
529 (GstMiniObjectCopyFunction) _gst_buffer_copy,
530 (GstMiniObjectDisposeFunction) _gst_buffer_dispose,
531 (GstMiniObjectFreeFunction) _gst_buffer_free);
533 GST_BUFFER_SLICE_SIZE (buffer) = size;
535 GST_BUFFER (buffer)->pool = NULL;
536 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
537 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
538 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
539 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
540 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
542 GST_BUFFER_MEM_LEN (buffer) = 0;
543 GST_BUFFER_META (buffer) = NULL;
549 * Creates a newly allocated buffer without any data.
553 * Returns: (transfer full): the new #GstBuffer.
556 gst_buffer_new (void)
558 GstBufferImpl *newbuf;
560 newbuf = g_slice_new (GstBufferImpl);
561 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
563 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
565 return GST_BUFFER_CAST (newbuf);
569 * gst_buffer_new_allocate:
570 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
572 * @size: the size in bytes of the new buffer's data.
573 * @params: (transfer none) (allow-none): optional parameters
575 * Tries to create a newly allocated buffer with data of the given size and
576 * extra parameters from @allocator. If the requested amount of memory can't be
577 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
579 * When @allocator is NULL, the default memory allocator will be used.
581 * Note that when @size == 0, the buffer will not have memory associated with it.
585 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
589 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
590 GstAllocationParams * params)
601 mem = gst_allocator_alloc (allocator, size, params);
602 if (G_UNLIKELY (mem == NULL))
608 newbuf = gst_buffer_new ();
611 _memory_add (newbuf, -1, mem);
613 GST_CAT_LOG (GST_CAT_BUFFER,
614 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
619 asize = sizeof (GstBufferImpl) + size;
620 data = g_slice_alloc (asize);
621 if (G_UNLIKELY (data == NULL))
624 newbuf = GST_BUFFER_CAST (data);
626 gst_buffer_init ((GstBufferImpl *) data, asize);
628 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
630 _memory_add (newbuf, -1, mem);
635 /* allocate memory and buffer, it might be interesting to do this but there
636 * are many complications. We need to keep the memory mapped to access the
637 * buffer fields and the memory for the buffer might be just very slow. We
638 * also need to do some more magic to get the alignment right. */
639 asize = sizeof (GstBufferImpl) + size;
640 mem = gst_allocator_alloc (allocator, asize, align);
641 if (G_UNLIKELY (mem == NULL))
644 /* map the data part and init the buffer in it, set the buffer size to 0 so
645 * that a finalize won't free the buffer */
646 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
647 gst_buffer_init ((GstBufferImpl *) data, 0);
648 gst_memory_unmap (mem);
650 /* strip off the buffer */
651 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
653 newbuf = GST_BUFFER_CAST (data);
654 GST_BUFFER_BUFMEM (newbuf) = mem;
657 _memory_add (newbuf, -1, gst_memory_ref (mem));
665 GST_CAT_WARNING (GST_CAT_BUFFER,
666 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
672 * gst_buffer_new_wrapped_full:
673 * @flags: #GstMemoryFlags
674 * @data: data to wrap
675 * @maxsize: allocated size of @data
676 * @offset: offset in @data
677 * @size: size of valid data
678 * @user_data: user_data
679 * @notify: called with @user_data when the memory is freed
681 * Allocate a new buffer that wraps the given memory. @data must point to
682 * @maxsize of memory, the wrapped buffer will have the region from @offset and
685 * When the buffer is destroyed, @notify will be called with @user_data.
687 * The prefix/padding must be filled with 0 if @flags contains
688 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
690 * Returns: (transfer full): a new #GstBuffer
693 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
694 gsize maxsize, gsize offset, gsize size, gpointer user_data,
695 GDestroyNotify notify)
699 newbuf = gst_buffer_new ();
700 gst_buffer_append_memory (newbuf,
701 gst_memory_new_wrapped (flags, data, maxsize, offset, size,
708 * gst_buffer_new_wrapped:
709 * @data: data to wrap
710 * @size: allocated size of @data
712 * Creates a new buffer that wraps the given @data. The memory will be freed
713 * with g_free and will be marked writable.
717 * Returns: (transfer full): a new #GstBuffer
720 gst_buffer_new_wrapped (gpointer data, gsize size)
722 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
726 * gst_buffer_n_memory:
727 * @buffer: a #GstBuffer.
729 * Get the amount of memory blocks that this buffer has.
731 * Returns: (transfer full): the amount of memory block in this buffer.
734 gst_buffer_n_memory (GstBuffer * buffer)
736 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
738 return GST_BUFFER_MEM_LEN (buffer);
742 * gst_buffer_prepend_memory:
744 * @m: (transfer full): a #GstMemory.
746 * Prepend the memory block @m to @b. This function takes ownership
747 * of @m and thus doesn't increase its refcount.
750 * gst_buffer_append_memory:
752 * @m: (transfer full): a #GstMemory.
754 * Append the memory block @m to @b. This function takes ownership
755 * of @m and thus doesn't increase its refcount.
758 * gst_buffer_insert_memory:
759 * @buffer: a #GstBuffer.
760 * @idx: the index to add the memory at, or -1 to append it to the end
761 * @mem: (transfer full): a #GstMemory.
763 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
764 * of @mem and thus doesn't increase its refcount.
767 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
769 g_return_if_fail (GST_IS_BUFFER (buffer));
770 g_return_if_fail (gst_buffer_is_writable (buffer));
771 g_return_if_fail (mem != NULL);
772 g_return_if_fail (idx == -1 ||
773 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
775 _memory_add (buffer, idx, mem);
779 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
782 GstMemory *mem, *mapped;
784 mem = GST_BUFFER_MEM_PTR (buffer, idx);
786 mapped = gst_memory_make_mapped (mem, info, flags);
791 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
792 gst_memory_unref (mem);
799 * gst_buffer_peek_memory:
800 * @buffer: a #GstBuffer.
803 * Get the memory block at @idx in @buffer. The memory block stays valid until
804 * the memory block in @buffer is removed, replaced or merged, typically with
805 * any call that modifies the memory in @buffer.
807 * Since this call does not influence the refcount of the memory,
808 * gst_memory_is_exclusive() can be used to check if @buffer is the sole owner
809 * of the returned memory.
811 * Returns: (transfer none): the #GstMemory at @idx.
814 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
818 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
819 len = GST_BUFFER_MEM_LEN (buffer);
820 g_return_val_if_fail (idx < len, NULL);
822 return GST_BUFFER_MEM_PTR (buffer, idx);
826 * gst_buffer_get_memory:
830 * Get the memory block at index @i in @buffer.
832 * Returns: (transfer full): a #GstMemory that contains the data of the
833 * memory block at @idx. Use gst_memory_unref () after usage.
836 * gst_buffer_get_all_memory:
839 * Get all the memory block in @buffer. The memory blocks will be merged
840 * into one large #GstMemory.
842 * Returns: (transfer full): a #GstMemory that contains the merged memory.
843 * Use gst_memory_unref () after usage.
846 * gst_buffer_get_memory_range:
847 * @buffer: a #GstBuffer.
851 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
852 * be merged into one large #GstMemory.
854 * If @length is -1, all memory starting from @idx is merged.
856 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
857 * blocks starting at @idx. Use gst_memory_unref () after usage.
860 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
864 GST_DEBUG ("idx %u, length %d", idx, length);
866 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
867 len = GST_BUFFER_MEM_LEN (buffer);
868 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
869 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
874 return _get_merged_memory (buffer, idx, length);
878 * gst_buffer_replace_memory:
881 * @m: (transfer full): a #GstMemory
883 * Replaces the memory block at index @i in @b with @m.
886 * gst_buffer_replace_all_memory:
888 * @m: (transfer full): a #GstMemory
890 * Replaces all memory in @b with @m.
893 * gst_buffer_replace_memory_range:
894 * @buffer: a #GstBuffer.
896 * @length: a length should not be 0
897 * @mem: (transfer full): a #GstMemory
899 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
901 * If @length is -1, all memory starting from @idx will be removed and
902 * replaced with @mem.
904 * @buffer should be writable.
907 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
912 g_return_if_fail (GST_IS_BUFFER (buffer));
913 g_return_if_fail (gst_buffer_is_writable (buffer));
914 len = GST_BUFFER_MEM_LEN (buffer);
915 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
916 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
921 _replace_memory (buffer, len, idx, length, mem);
925 * gst_buffer_remove_memory:
929 * Remove the memory block in @b at index @i.
932 * gst_buffer_remove_all_memory:
935 * Remove all the memory blocks in @b.
938 * gst_buffer_remove_memory_range:
939 * @buffer: a #GstBuffer.
943 * Remove @length memory blocks in @buffer starting from @idx.
945 * @length can be -1, in which case all memory starting from @idx is removed.
948 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
952 g_return_if_fail (GST_IS_BUFFER (buffer));
953 g_return_if_fail (gst_buffer_is_writable (buffer));
955 len = GST_BUFFER_MEM_LEN (buffer);
956 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
957 (length == -1 && idx < len) || length + idx <= len);
962 _replace_memory (buffer, len, idx, length, NULL);
966 * gst_buffer_find_memory:
967 * @buffer: a #GstBuffer.
970 * @idx: (out): pointer to index
971 * @length: (out): pointer to length
972 * @skip: (out): pointer to skip
974 * Find the memory blocks that span @size bytes starting from @offset
977 * When this function returns %TRUE, @idx will contain the index of the first
978 * memory bock where the byte for @offset can be found and @length contains the
979 * number of memory blocks containing the @size remaining bytes. @skip contains
980 * the number of bytes to skip in the memory bock at @idx to get to the byte
983 * @size can be -1 to get all the memory blocks after @idx.
985 * Returns: %TRUE when @size bytes starting from @offset could be found in
986 * @buffer and @idx, @length and @skip will be filled.
989 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
990 guint * idx, guint * length, gsize * skip)
994 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
995 g_return_val_if_fail (idx != NULL, FALSE);
996 g_return_val_if_fail (length != NULL, FALSE);
997 g_return_val_if_fail (skip != NULL, FALSE);
999 len = GST_BUFFER_MEM_LEN (buffer);
1002 for (i = 0; i < len; i++) {
1006 mem = GST_BUFFER_MEM_PTR (buffer, i);
1007 s = gst_memory_get_sizes (mem, NULL, NULL);
1010 /* block before offset, or empty block, skip */
1013 /* block after offset */
1015 /* first block, remember index and offset */
1019 /* return remaining blocks */
1026 /* count the amount of found bytes */
1028 if (found >= size) {
1029 /* we have enough bytes */
1030 *length = i - *idx + 1;
1039 * gst_buffer_get_sizes:
1041 * @of: a pointer to the offset
1042 * @ms: a pointer to the maxsize
1044 * Get the total size of the memory blocks in @b.
1046 * When not %NULL, @of will contain the offset of the data in the first
1047 * memory block in @buffer and @maxsize will contain the sum of the size
1048 * and @of and the amount of extra padding on the last memory block.
1049 * @of and @ms can be used to resize the buffer memory blocks with
1050 * gst_buffer_resize().
1052 * Returns: total size of the memory blocks in @b.
1055 * gst_buffer_get_size:
1058 * Get the total size of the memory blocks in @b.
1060 * Returns: total size of the memory blocks in @b.
1063 * gst_buffer_get_sizes_range:
1064 * @buffer: a #GstBuffer.
1067 * @offset: a pointer to the offset
1068 * @maxsize: a pointer to the maxsize
1070 * Get the total size of @length memory blocks stating from @idx in @buffer.
1072 * When not %NULL, @offset will contain the offset of the data in the
1073 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1074 * and @offset and the amount of extra padding on the memory block at @idx +
1076 * @offset and @maxsize can be used to resize the buffer memory blocks with
1077 * gst_buffer_resize_range().
1079 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1082 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1083 gsize * offset, gsize * maxsize)
1089 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1090 len = GST_BUFFER_MEM_LEN (buffer);
1091 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1092 (length == -1 && idx < len) || (length + idx <= len), 0);
1097 if (G_LIKELY (length == 1)) {
1099 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1100 size = gst_memory_get_sizes (mem, offset, maxsize);
1106 size = offs = extra = 0;
1107 for (i = idx; i < end; i++) {
1110 mem = GST_BUFFER_MEM_PTR (buffer, i);
1111 s = gst_memory_get_sizes (mem, &o, &ms);
1115 /* first size, take accumulated data before as the offset */
1119 /* save the amount of data after this block */
1120 extra = ms - (o + s);
1122 /* empty block, add as extra */
1129 *maxsize = offs + size + extra;
1135 * gst_buffer_resize:
1137 * @of: the offset adjustement
1138 * @s: the new size or -1 to just adjust the offset
1140 * Set the offset and total size of the memory blocks in @b.
1143 * gst_buffer_set_size:
1147 * Set the total size of the memory blocks in @b.
1150 * gst_buffer_resize_range:
1151 * @buffer: a #GstBuffer.
1154 * @offset: the offset adjustement
1155 * @size: the new size or -1 to just adjust the offset
1157 * Set the total size of the @length memory blocks starting at @idx in
1161 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1162 gssize offset, gssize size)
1165 gsize bsize, bufsize, bufoffs, bufmax;
1168 g_return_if_fail (gst_buffer_is_writable (buffer));
1169 g_return_if_fail (size >= -1);
1170 len = GST_BUFFER_MEM_LEN (buffer);
1171 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1172 (length == -1 && idx < len) || (length + idx <= len));
1177 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1179 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1180 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1181 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1183 /* we can't go back further than the current offset or past the end of the
1185 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1186 && bufoffs + offset <= bufmax));
1188 g_return_if_fail (bufsize >= offset);
1189 size = bufsize - offset;
1191 g_return_if_fail (bufmax >= bufoffs + offset + size);
1194 if (offset == 0 && size == bufsize)
1199 for (i = idx; i < end; i++) {
1202 mem = GST_BUFFER_MEM_PTR (buffer, i);
1203 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1206 /* last buffer always gets resized to the remaining size */
1209 /* shrink buffers before the offset */
1210 else if ((gssize) bsize <= offset) {
1212 noffs = offset - bsize;
1215 /* clip other buffers */
1217 left = MIN (bsize - offset, size);
1219 if (offset != 0 || left != bsize) {
1220 if (gst_memory_is_exclusive (mem)) {
1221 gst_memory_resize (mem, offset, left);
1225 if (GST_MEMORY_IS_NO_SHARE (mem))
1226 tmp = gst_memory_copy (mem, offset, left);
1228 tmp = gst_memory_share (mem, offset, left);
1230 gst_memory_unref (mem);
1237 GST_BUFFER_MEM_PTR (buffer, i) = mem;
1244 * @i: (out): info about the mapping
1245 * @f: flags for the mapping
1247 * This function fills @i with the #GstMapInfo of all merged memory blocks
1250 * @flags describe the desired access of the memory. When @flags is
1251 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1252 * gst_buffer_is_writable()).
1254 * When @buffer is writable but the memory isn't, a writable copy will
1255 * automatically be created and returned. The readonly copy of the buffer memory
1256 * will then also be replaced with this writable copy.
1258 * The memory in @i should be unmapped with gst_buffer_unmap() after usage.
1260 * Returns: %TRUE if the map succeeded and @i contains valid data.
1263 * gst_buffer_map_range:
1264 * @buffer: a #GstBuffer.
1267 * @info: (out): info about the mapping
1268 * @flags: flags for the mapping
1270 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1271 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1272 * from @idx are merged and mapped.
1274 * @flags describe the desired access of the memory. When @flags is
1275 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1276 * gst_buffer_is_writable()).
1278 * When @buffer is writable but the memory isn't, a writable copy will
1279 * automatically be created and returned. The readonly copy of the buffer memory
1280 * will then also be replaced with this writable copy.
1282 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1284 * Returns: %TRUE if the map succeeded and @info contains valid
1288 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1289 GstMapInfo * info, GstMapFlags flags)
1291 GstMemory *mem, *nmem;
1292 gboolean write, writable;
1295 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1296 g_return_val_if_fail (info != NULL, FALSE);
1297 len = GST_BUFFER_MEM_LEN (buffer);
1298 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1299 (length == -1 && idx < len) || (length > 0
1300 && length + idx <= len), FALSE);
1302 write = (flags & GST_MAP_WRITE) != 0;
1303 writable = gst_buffer_is_writable (buffer);
1305 /* check if we can write when asked for write access */
1306 if (G_UNLIKELY (write && !writable))
1312 mem = _get_merged_memory (buffer, idx, length);
1313 if (G_UNLIKELY (mem == NULL))
1316 /* now try to map */
1317 nmem = gst_memory_make_mapped (mem, info, flags);
1318 if (G_UNLIKELY (nmem == NULL))
1321 /* if we merged or when the map returned a different memory, we try to replace
1322 * the memory in the buffer */
1323 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1324 /* if the buffer is writable, replace the memory */
1326 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1329 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1330 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1339 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1340 g_critical ("write map requested on non-writable buffer");
1345 /* empty buffer, we need to return NULL */
1346 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1347 info->memory = NULL;
1355 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1362 * @buffer: a #GstBuffer.
1363 * @info: a #GstMapInfo
1365 * Release the memory previously mapped with gst_buffer_map().
1368 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1370 g_return_if_fail (GST_IS_BUFFER (buffer));
1371 g_return_if_fail (info != NULL);
1373 /* we need to check for NULL, it is possible that we tried to map a buffer
1374 * without memory and we should be able to unmap that fine */
1375 if (G_LIKELY (info->memory)) {
1376 gst_memory_unmap (info->memory, info);
1377 gst_memory_unref (info->memory);
1383 * @buffer: a #GstBuffer.
1384 * @offset: the offset to fill
1385 * @src: the source address
1386 * @size: the size to fill
1388 * Copy @size bytes from @src to @buffer at @offset.
1390 * Returns: The amount of bytes copied. This value can be lower than @size
1391 * when @buffer did not contain enough data.
1394 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1398 const guint8 *ptr = src;
1400 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1401 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1402 g_return_val_if_fail (src != NULL, 0);
1404 len = GST_BUFFER_MEM_LEN (buffer);
1407 for (i = 0; i < len && left > 0; i++) {
1412 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1413 if (info.size > offset) {
1414 /* we have enough */
1415 tocopy = MIN (info.size - offset, left);
1416 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1421 /* offset past buffer, skip */
1422 offset -= info.size;
1424 gst_memory_unmap (mem, &info);
1430 * gst_buffer_extract:
1431 * @buffer: a #GstBuffer.
1432 * @offset: the offset to extract
1433 * @dest: the destination address
1434 * @size: the size to extract
1436 * Copy @size bytes starting from @offset in @buffer to @dest.
1438 * Returns: The amount of bytes extracted. This value can be lower than @size
1439 * when @buffer did not contain enough data.
1442 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1447 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1448 g_return_val_if_fail (dest != NULL, 0);
1450 len = GST_BUFFER_MEM_LEN (buffer);
1453 for (i = 0; i < len && left > 0; i++) {
1458 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1459 if (info.size > offset) {
1460 /* we have enough */
1461 tocopy = MIN (info.size - offset, left);
1462 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1467 /* offset past buffer, skip */
1468 offset -= info.size;
1470 gst_memory_unmap (mem, &info);
1476 * gst_buffer_memcmp:
1477 * @buffer: a #GstBuffer.
1478 * @offset: the offset in @buffer
1479 * @mem: the memory to compare
1480 * @size: the size to compare
1482 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1484 * Returns: 0 if the memory is equal.
1487 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1491 const guint8 *ptr = mem;
1494 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1495 g_return_val_if_fail (mem != NULL, 0);
1497 len = GST_BUFFER_MEM_LEN (buffer);
1499 for (i = 0; i < len && size > 0 && res == 0; i++) {
1504 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1505 if (info.size > offset) {
1506 /* we have enough */
1507 tocmp = MIN (info.size - offset, size);
1508 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1513 /* offset past buffer, skip */
1514 offset -= info.size;
1516 gst_memory_unmap (mem, &info);
1522 * gst_buffer_memset:
1523 * @buffer: a #GstBuffer.
1524 * @offset: the offset in @buffer
1525 * @val: the value to set
1526 * @size: the size to set
1528 * Fill @buf with @size bytes with @val starting from @offset.
1530 * Returns: The amount of bytes filled. This value can be lower than @size
1531 * when @buffer did not contain enough data.
1534 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1538 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1539 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1541 len = GST_BUFFER_MEM_LEN (buffer);
1544 for (i = 0; i < len && left > 0; i++) {
1549 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1550 if (info.size > offset) {
1551 /* we have enough */
1552 toset = MIN (info.size - offset, left);
1553 memset ((guint8 *) info.data + offset, val, toset);
1557 /* offset past buffer, skip */
1558 offset -= info.size;
1560 gst_memory_unmap (mem, &info);
1566 * gst_buffer_copy_region:
1567 * @parent: a #GstBuffer.
1568 * @flags: the #GstBufferCopyFlags
1569 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1571 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1573 * Creates a sub-buffer from @parent at @offset and @size.
1574 * This sub-buffer uses the actual memory space of the parent buffer.
1575 * This function will copy the offset and timestamp fields when the
1576 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1577 * #GST_BUFFER_OFFSET_NONE.
1578 * If @offset equals 0 and @size equals the total size of @buffer, the
1579 * duration and offset end fields are also copied. If not they will be set
1580 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1584 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1588 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1589 gsize offset, gsize size)
1593 g_return_val_if_fail (buffer != NULL, NULL);
1595 /* create the new buffer */
1596 copy = gst_buffer_new ();
1598 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1599 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1601 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1607 * gst_buffer_append:
1608 * @buf1: (transfer full): the first source #GstBuffer to append.
1609 * @buf2: (transfer full): the second source #GstBuffer to append.
1611 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1612 * concatenation of the memory of @buf1 and @buf2.
1614 * Returns: (transfer full): the new #GstBuffer that contains the memory
1615 * of the two source buffers.
1618 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1622 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1623 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1625 buf1 = gst_buffer_make_writable (buf1);
1626 buf2 = gst_buffer_make_writable (buf2);
1628 len = GST_BUFFER_MEM_LEN (buf2);
1629 for (i = 0; i < len; i++) {
1632 mem = GST_BUFFER_MEM_PTR (buf2, i);
1633 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1634 _memory_add (buf1, -1, mem);
1637 /* we can calculate the duration too. Also make sure we're not messing
1638 * with invalid DURATIONS */
1639 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
1640 GST_BUFFER_DURATION_IS_VALID (buf2)) {
1642 GST_BUFFER_DURATION (buf1) += GST_BUFFER_DURATION (buf2);
1644 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
1645 /* set offset_end */
1646 GST_BUFFER_OFFSET_END (buf1) = GST_BUFFER_OFFSET_END (buf2);
1649 GST_BUFFER_MEM_LEN (buf2) = 0;
1650 gst_buffer_unref (buf2);
1656 * gst_buffer_get_meta:
1657 * @buffer: a #GstBuffer
1658 * @api: the #GType of an API
1660 * Get the metadata for @api on buffer. When there is no such
1661 * metadata, NULL is returned.
1663 * Returns: (transfer none): the metadata for @api on @buffer.
1666 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1669 GstMeta *result = NULL;
1671 g_return_val_if_fail (buffer != NULL, NULL);
1672 g_return_val_if_fail (api != 0, NULL);
1674 /* find GstMeta of the requested API */
1675 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1676 GstMeta *meta = &item->meta;
1677 if (meta->info->api == api) {
1686 * gst_buffer_add_meta:
1687 * @buffer: a #GstBuffer
1688 * @info: a #GstMetaInfo
1689 * @params: params for @info
1691 * Add metadata for @info to @buffer using the parameters in @params.
1693 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1696 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1700 GstMeta *result = NULL;
1703 g_return_val_if_fail (buffer != NULL, NULL);
1704 g_return_val_if_fail (info != NULL, NULL);
1705 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1707 /* create a new slice */
1708 size = ITEM_SIZE (info);
1709 item = g_slice_alloc (size);
1710 result = &item->meta;
1711 result->info = info;
1712 result->flags = GST_META_FLAG_NONE;
1714 GST_CAT_DEBUG (GST_CAT_BUFFER,
1715 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1716 g_type_name (info->type), info->size);
1718 /* call the init_func when needed */
1719 if (info->init_func)
1720 if (!info->init_func (result, params, buffer))
1723 /* and add to the list of metadata */
1724 item->next = GST_BUFFER_META (buffer);
1725 GST_BUFFER_META (buffer) = item;
1731 g_slice_free1 (size, item);
1737 * gst_buffer_remove_meta:
1738 * @buffer: a #GstBuffer
1741 * Remove the metadata for @meta on @buffer.
1743 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1744 * metadata was on @buffer.
1747 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1749 GstMetaItem *walk, *prev;
1751 g_return_val_if_fail (buffer != NULL, FALSE);
1752 g_return_val_if_fail (meta != NULL, FALSE);
1753 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1754 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
1757 /* find the metadata and delete */
1758 prev = GST_BUFFER_META (buffer);
1759 for (walk = prev; walk; walk = walk->next) {
1760 GstMeta *m = &walk->meta;
1762 const GstMetaInfo *info = meta->info;
1764 /* remove from list */
1765 if (GST_BUFFER_META (buffer) == walk)
1766 GST_BUFFER_META (buffer) = walk->next;
1768 prev->next = walk->next;
1769 /* call free_func if any */
1770 if (info->free_func)
1771 info->free_func (m, buffer);
1773 /* and free the slice */
1774 g_slice_free1 (ITEM_SIZE (info), walk);
1779 return walk != NULL;
1783 * gst_buffer_iterate_meta:
1784 * @buffer: a #GstBuffer
1785 * @state: an opaque state pointer
1787 * Retrieve the next #GstMeta after @current. If @state points
1788 * to %NULL, the first metadata is returned.
1790 * @state will be updated with an opage state pointer
1792 * Returns: (transfer none): The next #GstMeta or %NULL when there are
1796 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1800 g_return_val_if_fail (buffer != NULL, NULL);
1801 g_return_val_if_fail (state != NULL, NULL);
1803 meta = (GstMetaItem **) state;
1805 /* state NULL, move to first item */
1806 *meta = GST_BUFFER_META (buffer);
1808 /* state !NULL, move to next item in list */
1809 *meta = (*meta)->next;
1812 return &(*meta)->meta;
1818 * gst_buffer_foreach_meta:
1819 * @buffer: a #GstBuffer
1820 * @func: (scope call): a #GstBufferForeachMetaFunc to call
1821 * @user_data: (closure): user data passed to @func
1823 * Call @func with @user_data for each meta in @buffer.
1825 * @func can modify the passed meta pointer or its contents. The return value
1826 * of @func define if this function returns or if the remaining metadata items
1827 * in the buffer should be skipped.
1830 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
1833 GstMetaItem *walk, *prev, *next;
1835 g_return_if_fail (buffer != NULL);
1836 g_return_if_fail (func != NULL);
1838 /* find the metadata and delete */
1839 prev = GST_BUFFER_META (buffer);
1840 for (walk = prev; walk; walk = next) {
1844 m = new = &walk->meta;
1847 res = func (buffer, &new, user_data);
1850 const GstMetaInfo *info = m->info;
1852 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
1853 g_type_name (info->type));
1855 g_return_if_fail (gst_buffer_is_writable (buffer));
1856 g_return_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED));
1858 /* remove from list */
1859 if (GST_BUFFER_META (buffer) == walk)
1860 GST_BUFFER_META (buffer) = next;
1864 /* call free_func if any */
1865 if (info->free_func)
1866 info->free_func (m, buffer);
1868 /* and free the slice */
1869 g_slice_free1 (ITEM_SIZE (info), walk);