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 "gstminiobject.h"
127 #include "gstversion.h"
129 GType _gst_buffer_type = 0;
131 typedef struct _GstMetaItem GstMetaItem;
138 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
140 #define GST_BUFFER_MEM_MAX 16
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)
152 /* the memory blocks */
154 GstMemory *mem[GST_BUFFER_MEM_MAX];
156 /* memory of the buffer when allocated from 1 chunk */
159 /* FIXME, make metadata allocation more efficient by using part of the
166 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
168 GstMemory *mcur, *mprv;
169 gboolean have_offset = FALSE;
174 for (i = 0; i < len; i++) {
182 /* check if memory is contiguous */
183 if (!gst_memory_is_span (mprv, mcur, &poffs))
190 *parent = mprv->parent;
200 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
202 GstMemory **mem, *result;
204 mem = GST_BUFFER_MEM_ARRAY (buffer);
206 if (G_UNLIKELY (length == 0)) {
208 } else if (G_LIKELY (length == 1)) {
209 result = gst_memory_ref (mem[idx]);
211 GstMemory *parent = NULL;
212 gsize size, poffset = 0;
214 size = gst_buffer_get_size (buffer);
216 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
218 if (parent->flags & GST_MEMORY_FLAG_NO_SHARE) {
219 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
220 result = gst_memory_copy (parent, poffset, size);
222 result = gst_memory_share (parent, poffset, size);
225 gsize i, tocopy, left;
226 GstMapInfo sinfo, dinfo;
229 result = gst_allocator_alloc (NULL, size, NULL);
230 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
235 for (i = idx; i < length && left > 0; i++) {
236 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
237 tocopy = MIN (sinfo.size, left);
238 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
239 "memcpy for merge %p from memory %p", result, mem[i]);
240 memcpy (ptr, (guint8 *) sinfo.data, tocopy);
243 gst_memory_unmap (mem[i], &sinfo);
245 gst_memory_unmap (result, &dinfo);
252 _replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
258 GST_LOG ("buffer %p replace %u-%u with memory %p", buffer, idx, end, mem);
260 /* unref old memory */
261 for (i = idx; i < end; i++)
262 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
265 /* replace with single memory */
266 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
272 g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
273 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
275 GST_BUFFER_MEM_LEN (buffer) = len - length;
279 _memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
281 guint i, len = GST_BUFFER_MEM_LEN (buffer);
283 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
284 /* too many buffer, span them. */
285 /* FIXME, there is room for improvement here: We could only try to merge
286 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
287 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
288 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
290 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
291 /* we now have 1 single spanned buffer */
298 for (i = len; i > idx; i--) {
299 /* move buffers to insert, FIXME, we need to insert first and then merge */
300 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
302 /* and insert the new buffer */
303 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
304 GST_BUFFER_MEM_LEN (buffer) = len + 1;
307 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
310 _priv_gst_buffer_initialize (void)
312 _gst_buffer_type = gst_buffer_get_type ();
316 * gst_buffer_copy_into:
317 * @dest: a destination #GstBuffer
318 * @src: a source #GstBuffer
319 * @flags: flags indicating what metadata fields should be copied.
320 * @offset: offset to copy from
321 * @size: total size to copy. If -1, all data is copied.
323 * Copies the information from @src into @dest.
325 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
326 * the memory from @src will be appended to @dest.
328 * @flags indicate which fields will be copied.
331 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
332 GstBufferCopyFlags flags, gsize offset, gsize size)
336 gboolean region = FALSE;
338 g_return_if_fail (dest != NULL);
339 g_return_if_fail (src != NULL);
341 /* nothing to copy if the buffers are the same */
342 if (G_UNLIKELY (dest == src))
345 g_return_if_fail (gst_buffer_is_writable (dest));
347 bufsize = gst_buffer_get_size (src);
348 g_return_if_fail (bufsize >= offset);
352 size = bufsize - offset;
355 g_return_if_fail (bufsize >= offset + size);
357 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
358 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
361 if (flags & GST_BUFFER_COPY_FLAGS) {
363 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
366 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
368 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
369 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
370 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
371 if (size == bufsize) {
372 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
373 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
376 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
377 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
378 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
379 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
380 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
384 if (flags & GST_BUFFER_COPY_MEMORY) {
386 gsize skip, left, len, i, bsize;
388 len = GST_BUFFER_MEM_LEN (src);
392 /* copy and make regions of the memory */
393 for (i = 0; i < len && left > 0; i++) {
394 mem = GST_BUFFER_MEM_PTR (src, i);
395 bsize = gst_memory_get_sizes (mem, NULL, NULL);
398 /* don't copy buffer */
403 tocopy = MIN (bsize - skip, left);
404 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE) {
405 /* no share, always copy then */
406 mem = gst_memory_copy (mem, skip, tocopy);
408 } else if (tocopy < bsize) {
409 /* we need to clip something */
410 mem = gst_memory_share (mem, skip, tocopy);
413 mem = gst_memory_ref (mem);
415 _memory_add (dest, -1, mem);
419 if (flags & GST_BUFFER_COPY_MERGE) {
420 len = GST_BUFFER_MEM_LEN (dest);
421 _replace_memory (dest, len, 0, len, _get_merged_memory (dest, 0, len));
425 if (flags & GST_BUFFER_COPY_META) {
426 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
427 GstMeta *meta = &walk->meta;
428 const GstMetaInfo *info = meta->info;
430 if (info->transform_func) {
431 GstMetaTransformCopy copy_data;
433 copy_data.region = region;
434 copy_data.offset = offset;
435 copy_data.size = size;
437 info->transform_func (dest, meta, src,
438 _gst_meta_transform_copy, ©_data);
445 _gst_buffer_copy (GstBuffer * buffer)
449 g_return_val_if_fail (buffer != NULL, NULL);
451 /* create a fresh new buffer */
452 copy = gst_buffer_new ();
454 /* we simply copy everything from our parent */
455 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
460 /* the default dispose function revives the buffer and returns it to the
461 * pool when there is a pool */
463 _gst_buffer_dispose (GstBuffer * buffer)
467 /* no pool, do free */
468 if ((pool = buffer->pool) == NULL)
471 /* keep the buffer alive */
472 gst_buffer_ref (buffer);
473 /* return the buffer to the pool */
474 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
475 gst_buffer_pool_release_buffer (pool, buffer);
481 _gst_buffer_free (GstBuffer * buffer)
483 GstMetaItem *walk, *next;
487 g_return_if_fail (buffer != NULL);
489 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
492 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
493 GstMeta *meta = &walk->meta;
494 const GstMetaInfo *info = meta->info;
496 /* call free_func if any */
498 info->free_func (meta, buffer);
501 /* and free the slice */
502 g_slice_free1 (ITEM_SIZE (info), walk);
505 /* get the size, when unreffing the memory, we could also unref the buffer
507 msize = GST_MINI_OBJECT_SIZE (buffer);
509 /* free our memory */
510 len = GST_BUFFER_MEM_LEN (buffer);
511 for (i = 0; i < len; i++)
512 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
514 /* we set msize to 0 when the buffer is part of the memory block */
516 g_slice_free1 (msize, buffer);
518 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
522 gst_buffer_init (GstBufferImpl * buffer, gsize size)
524 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type, size);
526 buffer->buffer.mini_object.copy =
527 (GstMiniObjectCopyFunction) _gst_buffer_copy;
528 buffer->buffer.mini_object.dispose =
529 (GstMiniObjectDisposeFunction) _gst_buffer_dispose;
530 buffer->buffer.mini_object.free =
531 (GstMiniObjectFreeFunction) _gst_buffer_free;
533 GST_BUFFER (buffer)->pool = NULL;
534 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
535 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
536 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
537 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
538 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
540 GST_BUFFER_MEM_LEN (buffer) = 0;
541 GST_BUFFER_META (buffer) = NULL;
547 * Creates a newly allocated buffer without any data.
551 * Returns: (transfer full): the new #GstBuffer.
554 gst_buffer_new (void)
556 GstBufferImpl *newbuf;
558 newbuf = g_slice_new (GstBufferImpl);
559 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
561 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
563 return GST_BUFFER_CAST (newbuf);
567 * gst_buffer_new_allocate:
568 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
570 * @size: the size in bytes of the new buffer's data.
571 * @params: (transfer none) (allow-none): optional parameters
573 * Tries to create a newly allocated buffer with data of the given size and
574 * extra parameters from @allocator. If the requested amount of memory can't be
575 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
577 * When @allocator is NULL, the default memory allocator will be used.
579 * Note that when @size == 0, the buffer will not have memory associated with it.
583 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
587 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
588 GstAllocationParams * params)
599 mem = gst_allocator_alloc (allocator, size, params);
600 if (G_UNLIKELY (mem == NULL))
606 newbuf = gst_buffer_new ();
609 _memory_add (newbuf, -1, mem);
611 GST_CAT_LOG (GST_CAT_BUFFER,
612 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
617 asize = sizeof (GstBufferImpl) + size;
618 data = g_slice_alloc (asize);
619 if (G_UNLIKELY (data == NULL))
622 newbuf = GST_BUFFER_CAST (data);
624 gst_buffer_init ((GstBufferImpl *) data, asize);
626 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
628 _memory_add (newbuf, -1, mem);
633 /* allocate memory and buffer, it might be interesting to do this but there
634 * are many complications. We need to keep the memory mapped to access the
635 * buffer fields and the memory for the buffer might be just very slow. We
636 * also need to do some more magic to get the alignment right. */
637 asize = sizeof (GstBufferImpl) + size;
638 mem = gst_allocator_alloc (allocator, asize, align);
639 if (G_UNLIKELY (mem == NULL))
642 /* map the data part and init the buffer in it, set the buffer size to 0 so
643 * that a finalize won't free the buffer */
644 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
645 gst_buffer_init ((GstBufferImpl *) data, 0);
646 gst_memory_unmap (mem);
648 /* strip off the buffer */
649 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
651 newbuf = GST_BUFFER_CAST (data);
652 GST_BUFFER_BUFMEM (newbuf) = mem;
655 _memory_add (newbuf, -1, gst_memory_ref (mem));
663 GST_CAT_WARNING (GST_CAT_BUFFER,
664 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
670 * gst_buffer_new_wrapped_full:
671 * @flags: #GstMemoryFlags
672 * @data: data to wrap
673 * @maxsize: allocated size of @data
674 * @offset: offset in @data
675 * @size: size of valid data
676 * @user_data: user_data
677 * @notify: called with @user_data when the memory is freed
679 * Allocate a new buffer that wraps the given memory. @data must point to
680 * @maxsize of memory, the wrapped buffer will have the region from @offset and
683 * When the buffer is destroyed, @notify will be called with @user_data.
685 * The prefix/padding must be filled with 0 if @flags contains
686 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
688 * Returns: (transfer full): a new #GstBuffer
691 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
692 gsize maxsize, gsize offset, gsize size, gpointer user_data,
693 GDestroyNotify notify)
697 newbuf = gst_buffer_new ();
698 gst_buffer_append_memory (newbuf,
699 gst_memory_new_wrapped (flags, data, maxsize, offset, size,
706 * gst_buffer_new_wrapped:
707 * @data: data to wrap
708 * @size: allocated size of @data
710 * Creates a new buffer that wraps the given @data. The memory will be freed
711 * with g_free and will be marked writable.
715 * Returns: (transfer full): a new #GstBuffer
718 gst_buffer_new_wrapped (gpointer data, gsize size)
720 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
724 * gst_buffer_n_memory:
725 * @buffer: a #GstBuffer.
727 * Get the amount of memory blocks that this buffer has.
729 * Returns: (transfer full): the amount of memory block in this buffer.
732 gst_buffer_n_memory (GstBuffer * buffer)
734 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
736 return GST_BUFFER_MEM_LEN (buffer);
740 * gst_buffer_insert_memory:
741 * @buffer: a #GstBuffer.
742 * @idx: the index to add the memory at, or -1 to append it to the end
743 * @mem: (transfer full): a #GstMemory.
745 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
746 * of @mem and thus doesn't increase its refcount.
749 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
751 g_return_if_fail (GST_IS_BUFFER (buffer));
752 g_return_if_fail (gst_buffer_is_writable (buffer));
753 g_return_if_fail (mem != NULL);
754 g_return_if_fail (idx == -1 ||
755 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
757 _memory_add (buffer, idx, mem);
761 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
764 GstMemory *mem, *mapped;
766 mem = GST_BUFFER_MEM_PTR (buffer, idx);
768 mapped = gst_memory_make_mapped (mem, info, flags);
773 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
774 gst_memory_unref (mem);
781 * gst_buffer_peek_memory:
782 * @buffer: a #GstBuffer.
785 * Get the memory block at @idx in @buffer. The memory block stays valid until
786 * the memory block in @buffer is removed, replaced or merged, typically with
787 * any call that modifies the memory in @buffer.
789 * Since this call does not influence the refcount of the memory,
790 * gst_memory_is_exclusive() can be used to check if @buffer is the sole owner
791 * of the returned memory.
793 * Returns: (transfer none): the #GstMemory at @idx.
796 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
800 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
801 len = GST_BUFFER_MEM_LEN (buffer);
802 g_return_val_if_fail (idx < len, NULL);
804 return GST_BUFFER_MEM_PTR (buffer, idx);
808 * gst_buffer_get_memory_range:
809 * @buffer: a #GstBuffer.
813 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
814 * be merged into one large #GstMemory.
816 * If @length is -1, all memory starting from @idx is merged.
818 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
819 * blocks starting at @idx. Use gst_memory_unref () after usage.
822 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
826 GST_DEBUG ("idx %u, length %d", idx, length);
828 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
829 len = GST_BUFFER_MEM_LEN (buffer);
830 g_return_val_if_fail ((length == -1 && idx < len) ||
831 (length > 0 && length + idx <= len), NULL);
836 return _get_merged_memory (buffer, idx, length);
840 * gst_buffer_replace_memory_range:
841 * @buffer: a #GstBuffer.
843 * @length: a length should not be 0
844 * @mem: (transfer full): a #GstMemory
846 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
848 * If @length is -1, all memory starting from @idx will be removed and
849 * replaced with @mem.
851 * @buffer should be writable.
854 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
859 g_return_if_fail (GST_IS_BUFFER (buffer));
860 g_return_if_fail (gst_buffer_is_writable (buffer));
861 len = GST_BUFFER_MEM_LEN (buffer);
862 g_return_if_fail ((length == -1 && idx < len) || (length > 0
863 && length + idx <= len));
868 _replace_memory (buffer, len, idx, length, mem);
872 * gst_buffer_remove_memory_range:
873 * @buffer: a #GstBuffer.
877 * Remove @length memory blocks in @buffer starting from @idx.
879 * @length can be -1, in which case all memory starting from @idx is removed.
882 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
886 g_return_if_fail (GST_IS_BUFFER (buffer));
887 g_return_if_fail (gst_buffer_is_writable (buffer));
889 len = GST_BUFFER_MEM_LEN (buffer);
890 g_return_if_fail ((length == -1 && idx < len) || length + idx <= len);
895 _replace_memory (buffer, len, idx, length, NULL);
899 * gst_buffer_find_memory:
900 * @buffer: a #GstBuffer.
903 * @idx: (out): pointer to index
904 * @length: (out): pointer to length
905 * @skip: (out): pointer to skip
907 * Find the memory blocks that span @size bytes starting from @offset
910 * When this function returns %TRUE, @idx will contain the index of the first
911 * memory bock where the byte for @offset can be found and @length contains the
912 * number of memory blocks containing the @size remaining bytes. @skip contains
913 * the number of bytes to skip in the memory bock at @idx to get to the byte
916 * @size can be -1 to get all the memory blocks after @idx.
918 * Returns: %TRUE when @size bytes starting from @offset could be found in
919 * @buffer and @idx, @length and @skip will be filled.
922 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
923 guint * idx, guint * length, gsize * skip)
927 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
928 g_return_val_if_fail (idx != NULL, FALSE);
929 g_return_val_if_fail (length != NULL, FALSE);
930 g_return_val_if_fail (skip != NULL, FALSE);
932 len = GST_BUFFER_MEM_LEN (buffer);
935 for (i = 0; i < len; i++) {
939 mem = GST_BUFFER_MEM_PTR (buffer, i);
940 s = gst_memory_get_sizes (mem, NULL, NULL);
943 /* block before offset, or empty block, skip */
946 /* block after offset */
948 /* first block, remember index and offset */
952 /* return remaining blocks */
959 /* count the amount of found bytes */
962 /* we have enough bytes */
963 *length = i - *idx + 1;
972 * gst_buffer_get_sizes:
973 * @buffer: a #GstBuffer.
974 * @offset: a pointer to the offset
975 * @maxsize: a pointer to the maxsize
977 * Get the total size of all memory blocks in @buffer.
979 * When not %NULL, @offset will contain the offset of the data in the first
980 * memory block in @buffer and @maxsize will contain the sum of the size
981 * and @offset and the amount of extra padding on the last memory block.
982 * @offset and @maxsize can be used to resize the buffer with
983 * gst_buffer_resize().
985 * Returns: the total size of the memory in @buffer.
988 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
994 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
996 len = GST_BUFFER_MEM_LEN (buffer);
998 if (G_LIKELY (len == 1)) {
1000 mem = GST_BUFFER_MEM_PTR (buffer, 0);
1001 size = gst_memory_get_sizes (mem, offset, maxsize);
1006 size = offs = extra = 0;
1007 for (i = 0; i < len; i++) {
1010 mem = GST_BUFFER_MEM_PTR (buffer, i);
1011 s = gst_memory_get_sizes (mem, &o, &ms);
1015 /* first size, take accumulated data before as the offset */
1019 /* save the amount of data after this block */
1020 extra = ms - (o + s);
1022 /* empty block, add as extra */
1029 *maxsize = offs + size + extra;
1035 * gst_buffer_resize:
1036 * @buffer: a #GstBuffer.
1037 * @offset: the offset adjustement
1038 * @size: the new size or -1 to just adjust the offset
1040 * Set the total size of the buffer
1043 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
1047 gsize bsize, bufsize, bufoffs, bufmax;
1050 g_return_if_fail (gst_buffer_is_writable (buffer));
1051 g_return_if_fail (size >= -1);
1053 bufsize = gst_buffer_get_sizes (buffer, &bufoffs, &bufmax);
1055 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1056 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1057 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1059 /* we can't go back further than the current offset or past the end of the
1061 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1062 && bufoffs + offset <= bufmax));
1064 g_return_if_fail (bufsize >= offset);
1065 size = bufsize - offset;
1067 g_return_if_fail (bufmax >= bufoffs + offset + size);
1070 if (offset == 0 && size == bufsize)
1073 len = GST_BUFFER_MEM_LEN (buffer);
1076 for (i = 0; i < len; i++) {
1079 mem = GST_BUFFER_MEM_PTR (buffer, i);
1080 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1083 /* last buffer always gets resized to the remaining size */
1086 /* shrink buffers before the offset */
1087 else if ((gssize) bsize <= offset) {
1089 noffs = offset - bsize;
1092 /* clip other buffers */
1094 left = MIN (bsize - offset, size);
1096 if (offset != 0 || left != bsize) {
1097 if (gst_memory_is_exclusive (mem)) {
1098 gst_memory_resize (mem, offset, left);
1102 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
1103 tmp = gst_memory_copy (mem, offset, left);
1105 tmp = gst_memory_share (mem, offset, left);
1107 gst_memory_unref (mem);
1114 GST_BUFFER_MEM_PTR (buffer, i) = mem;
1119 * gst_buffer_map_range:
1120 * @buffer: a #GstBuffer.
1123 * @info: (out): info about the mapping
1124 * @flags: flags for the mapping
1126 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1127 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1128 * from @idx are merged and mapped.
1129 * @flags describe the desired access of the memory. When @flags is
1130 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1131 * gst_buffer_is_writable()).
1133 * When @buffer is writable but the memory isn't, a writable copy will
1134 * automatically be created and returned. The readonly copy of the buffer memory
1135 * will then also be replaced with this writable copy.
1137 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1139 * Returns: (transfer full): %TRUE if the map succeeded and @info contains valid
1143 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1144 GstMapInfo * info, GstMapFlags flags)
1146 GstMemory *mem, *nmem;
1147 gboolean write, writable;
1150 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1151 g_return_val_if_fail (info != NULL, FALSE);
1152 len = GST_BUFFER_MEM_LEN (buffer);
1155 g_return_val_if_fail ((length == -1 && idx < len) || (length > 0
1156 && length + idx <= len), FALSE);
1158 write = (flags & GST_MAP_WRITE) != 0;
1159 writable = gst_buffer_is_writable (buffer);
1161 /* check if we can write when asked for write access */
1162 if (G_UNLIKELY (write && !writable))
1168 mem = _get_merged_memory (buffer, idx, length);
1169 if (G_UNLIKELY (mem == NULL))
1172 /* now try to map */
1173 nmem = gst_memory_make_mapped (mem, info, flags);
1174 if (G_UNLIKELY (nmem == NULL))
1177 /* if we merged or when the map returned a different memory, we try to replace
1178 * the memory in the buffer */
1179 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1180 /* if the buffer is writable, replace the memory */
1182 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1185 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1186 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1195 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1196 g_critical ("write map requested on non-writable buffer");
1201 /* empty buffer, we need to return NULL */
1202 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1203 info->memory = NULL;
1211 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1218 * @buffer: a #GstBuffer.
1219 * @info: a #GstMapInfo
1221 * Release the memory previously mapped with gst_buffer_map().
1224 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1226 g_return_if_fail (GST_IS_BUFFER (buffer));
1227 g_return_if_fail (info != NULL);
1229 /* we need to check for NULL, it is possible that we tried to map a buffer
1230 * without memory and we should be able to unmap that fine */
1231 if (G_LIKELY (info->memory)) {
1232 gst_memory_unmap (info->memory, info);
1233 gst_memory_unref (info->memory);
1239 * @buffer: a #GstBuffer.
1240 * @offset: the offset to fill
1241 * @src: the source address
1242 * @size: the size to fill
1244 * Copy @size bytes from @src to @buffer at @offset.
1246 * Returns: The amount of bytes copied. This value can be lower than @size
1247 * when @buffer did not contain enough data.
1250 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1254 const guint8 *ptr = src;
1256 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1257 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1258 g_return_val_if_fail (src != NULL, 0);
1260 len = GST_BUFFER_MEM_LEN (buffer);
1263 for (i = 0; i < len && left > 0; i++) {
1268 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1269 if (info.size > offset) {
1270 /* we have enough */
1271 tocopy = MIN (info.size - offset, left);
1272 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1277 /* offset past buffer, skip */
1278 offset -= info.size;
1280 gst_memory_unmap (mem, &info);
1286 * gst_buffer_extract:
1287 * @buffer: a #GstBuffer.
1288 * @offset: the offset to extract
1289 * @dest: the destination address
1290 * @size: the size to extract
1292 * Copy @size bytes starting from @offset in @buffer to @dest.
1294 * Returns: The amount of bytes extracted. This value can be lower than @size
1295 * when @buffer did not contain enough data.
1298 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1303 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1304 g_return_val_if_fail (dest != NULL, 0);
1306 len = GST_BUFFER_MEM_LEN (buffer);
1309 for (i = 0; i < len && left > 0; i++) {
1314 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1315 if (info.size > offset) {
1316 /* we have enough */
1317 tocopy = MIN (info.size - offset, left);
1318 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1323 /* offset past buffer, skip */
1324 offset -= info.size;
1326 gst_memory_unmap (mem, &info);
1332 * gst_buffer_memcmp:
1333 * @buffer: a #GstBuffer.
1334 * @offset: the offset in @buffer
1335 * @mem: the memory to compare
1336 * @size: the size to compare
1338 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1340 * Returns: 0 if the memory is equal.
1343 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1347 const guint8 *ptr = mem;
1350 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1351 g_return_val_if_fail (mem != NULL, 0);
1353 len = GST_BUFFER_MEM_LEN (buffer);
1355 for (i = 0; i < len && size > 0 && res == 0; i++) {
1360 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1361 if (info.size > offset) {
1362 /* we have enough */
1363 tocmp = MIN (info.size - offset, size);
1364 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1369 /* offset past buffer, skip */
1370 offset -= info.size;
1372 gst_memory_unmap (mem, &info);
1378 * gst_buffer_memset:
1379 * @buffer: a #GstBuffer.
1380 * @offset: the offset in @buffer
1381 * @val: the value to set
1382 * @size: the size to set
1384 * Fill @buf with @size bytes with @val starting from @offset.
1386 * Returns: The amount of bytes filled. This value can be lower than @size
1387 * when @buffer did not contain enough data.
1390 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1394 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1395 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1397 len = GST_BUFFER_MEM_LEN (buffer);
1400 for (i = 0; i < len && left > 0; i++) {
1405 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1406 if (info.size > offset) {
1407 /* we have enough */
1408 toset = MIN (info.size - offset, left);
1409 memset ((guint8 *) info.data + offset, val, toset);
1413 /* offset past buffer, skip */
1414 offset -= info.size;
1416 gst_memory_unmap (mem, &info);
1422 * gst_buffer_copy_region:
1423 * @parent: a #GstBuffer.
1424 * @flags: the #GstBufferCopyFlags
1425 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1427 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1429 * Creates a sub-buffer from @parent at @offset and @size.
1430 * This sub-buffer uses the actual memory space of the parent buffer.
1431 * This function will copy the offset and timestamp fields when the
1432 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1433 * #GST_BUFFER_OFFSET_NONE.
1434 * If @offset equals 0 and @size equals the total size of @buffer, the
1435 * duration and offset end fields are also copied. If not they will be set
1436 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1440 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1444 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1445 gsize offset, gsize size)
1449 g_return_val_if_fail (buffer != NULL, NULL);
1451 /* create the new buffer */
1452 copy = gst_buffer_new ();
1454 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1455 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1457 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1463 * gst_buffer_append:
1464 * @buf1: (transfer full): the first source #GstBuffer to append.
1465 * @buf2: (transfer full): the second source #GstBuffer to append.
1467 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1468 * concatenation of the memory of @buf1 and @buf2.
1470 * Returns: (transfer full): the new #GstBuffer that contains the memory
1471 * of the two source buffers.
1474 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1478 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1479 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1481 buf1 = gst_buffer_make_writable (buf1);
1482 buf2 = gst_buffer_make_writable (buf2);
1484 len = GST_BUFFER_MEM_LEN (buf2);
1485 for (i = 0; i < len; i++) {
1488 mem = GST_BUFFER_MEM_PTR (buf2, i);
1489 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1490 _memory_add (buf1, -1, mem);
1493 /* we can calculate the duration too. Also make sure we're not messing
1494 * with invalid DURATIONS */
1495 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
1496 GST_BUFFER_DURATION_IS_VALID (buf2)) {
1498 GST_BUFFER_DURATION (buf1) += GST_BUFFER_DURATION (buf2);
1500 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
1501 /* set offset_end */
1502 GST_BUFFER_OFFSET_END (buf1) = GST_BUFFER_OFFSET_END (buf2);
1505 GST_BUFFER_MEM_LEN (buf2) = 0;
1506 gst_buffer_unref (buf2);
1512 * gst_buffer_get_meta:
1513 * @buffer: a #GstBuffer
1514 * @api: the #GType of an API
1516 * Get the metadata for @api on buffer. When there is no such
1517 * metadata, NULL is returned.
1519 * Returns: the metadata for @api on @buffer.
1522 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1525 GstMeta *result = NULL;
1527 g_return_val_if_fail (buffer != NULL, NULL);
1528 g_return_val_if_fail (api != 0, NULL);
1530 /* find GstMeta of the requested API */
1531 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1532 GstMeta *meta = &item->meta;
1533 if (meta->info->api == api) {
1542 * gst_buffer_add_meta:
1543 * @buffer: a #GstBuffer
1544 * @info: a #GstMetaInfo
1545 * @params: params for @info
1547 * Add metadata for @info to @buffer using the parameters in @params.
1549 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1552 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1556 GstMeta *result = NULL;
1559 g_return_val_if_fail (buffer != NULL, NULL);
1560 g_return_val_if_fail (info != NULL, NULL);
1561 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1563 /* create a new slice */
1564 size = ITEM_SIZE (info);
1565 item = g_slice_alloc (size);
1566 result = &item->meta;
1567 result->info = info;
1568 result->flags = GST_META_FLAG_NONE;
1570 GST_CAT_DEBUG (GST_CAT_BUFFER,
1571 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1572 g_type_name (info->type), info->size);
1574 /* call the init_func when needed */
1575 if (info->init_func)
1576 if (!info->init_func (result, params, buffer))
1579 /* and add to the list of metadata */
1580 item->next = GST_BUFFER_META (buffer);
1581 GST_BUFFER_META (buffer) = item;
1587 g_slice_free1 (size, item);
1593 * gst_buffer_remove_meta:
1594 * @buffer: a #GstBuffer
1597 * Remove the metadata for @meta on @buffer.
1599 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1600 * metadata was on @buffer.
1603 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1605 GstMetaItem *walk, *prev;
1607 g_return_val_if_fail (buffer != NULL, FALSE);
1608 g_return_val_if_fail (meta != NULL, FALSE);
1609 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1611 /* find the metadata and delete */
1612 prev = GST_BUFFER_META (buffer);
1613 for (walk = prev; walk; walk = walk->next) {
1614 GstMeta *m = &walk->meta;
1616 const GstMetaInfo *info = meta->info;
1618 /* remove from list */
1619 if (GST_BUFFER_META (buffer) == walk)
1620 GST_BUFFER_META (buffer) = walk->next;
1622 prev->next = walk->next;
1623 /* call free_func if any */
1624 if (info->free_func)
1625 info->free_func (m, buffer);
1627 /* and free the slice */
1628 g_slice_free1 (ITEM_SIZE (info), walk);
1633 return walk != NULL;
1637 * gst_buffer_iterate_meta:
1638 * @buffer: a #GstBuffer
1639 * @state: an opaque state pointer
1641 * Retrieve the next #GstMeta after @current. If @state points
1642 * to %NULL, the first metadata is returned.
1644 * @state will be updated with an opage state pointer
1646 * Returns: The next #GstMeta or %NULL when there are no more items.
1649 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1653 g_return_val_if_fail (buffer != NULL, NULL);
1654 g_return_val_if_fail (state != NULL, NULL);
1656 meta = (GstMetaItem **) state;
1658 /* state NULL, move to first item */
1659 *meta = GST_BUFFER_META (buffer);
1661 /* state !NULL, move to next item in list */
1662 *meta = (*meta)->next;
1665 return &(*meta)->meta;
1671 * gst_buffer_foreach_meta:
1672 * @buffer: a #GstBuffer
1673 * @func: (scope call): a #GstBufferForeachMetaFunc to call
1674 * @user_data: (closure): user data passed to @func
1676 * Call @func with @user_data for each meta in @buffer.
1678 * @func can modify the passed meta pointer or its contents. The return value
1679 * of @func define if this function returns or if the remaining metadata items
1680 * in the buffer should be skipped.
1683 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
1686 GstMetaItem *walk, *prev, *next;
1688 g_return_if_fail (buffer != NULL);
1689 g_return_if_fail (func != NULL);
1691 /* find the metadata and delete */
1692 prev = GST_BUFFER_META (buffer);
1693 for (walk = prev; walk; walk = next) {
1697 m = new = &walk->meta;
1700 res = func (buffer, &new, user_data);
1703 const GstMetaInfo *info = m->info;
1705 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
1706 g_type_name (info->type));
1708 g_return_if_fail (gst_buffer_is_writable (buffer));
1710 /* remove from list */
1711 if (GST_BUFFER_META (buffer) == walk)
1712 GST_BUFFER_META (buffer) = next;
1716 /* call free_func if any */
1717 if (info->free_func)
1718 info->free_func (m, buffer);
1720 /* and free the slice */
1721 g_slice_free1 (ITEM_SIZE (info), walk);