GST_DEBUG_CATEGORY_STATIC (gst_qt_mux_debug);
#define GST_CAT_DEFAULT gst_qt_mux_debug
+/* Hacker notes.
+ *
+ * The basic building blocks of MP4 files are:
+ * - an 'ftyp' box at the very start
+ * - an 'mdat' box which contains the raw audio/video/subtitle data;
+ * this is just a bunch of bytes, completely unframed and possibly
+ * unordered with no additional meta-information
+ * - a 'moov' box that contains information about the different streams
+ * and what they contain, as well as sample tables for each stream
+ * that tell the demuxer where in the mdat box each buffer/sample is
+ * and what its duration/timestamp etc. is, and whether it's a
+ * keyframe etc.
+ * Additionally, fragmented MP4 works by writing chunks of data in
+ * pairs of 'moof' and 'mdat' boxes:
+ * - 'moof' boxes, header preceding each mdat fragment describing the
+ * contents, like a moov but only for that fragment.
+ * - a 'mfra' box for Fragmented MP4, which is written at the end and
+ * contains a summary of all fragments and seek tables.
+ *
+ * Currently mp4mux can work in 3 different modes / generate 3 types
+ * of output files/streams:
+ *
+ * - Normal mp4: mp4mux will write a little ftyp identifier at the
+ * beginning, then start an mdat box into which it will write all the
+ * sample data. At EOS it will then write the moov header with track
+ * headers and sample tables at the end of the file, and rewrite the
+ * start of the file to fix up the mdat box size at the beginning.
+ * It has to wait for EOS to write the moov (which includes the
+ * sample tables) because it doesn't know how much space those
+ * tables will be. The output downstream must be seekable to rewrite
+ * the mdat box at EOS.
+ *
+ * - Fragmented mp4: moov header with track headers at start
+ * but no sample table), followed by N fragments, each containing
+ * track headers with sample tables followed by some data. Downstream
+ * does not need to be seekable if the 'streamable' flag is TRUE,
+ * as the final mfra and total duration will be omitted.
+ *
+ * - Fast-start mp4: the goal here is to create a file where the moov
+ * headers are at the beginning; what mp4mux will do is write all
+ * sample data into a temp file and build moov header plus sample
+ * tables in memory and then when EOS comes, it will push out the
+ * moov header plus sample tables at the beginning, followed by the
+ * mdat sample data at the end which is read in from the temp file
+ * Files created in this mode are better for streaming over the
+ * network, since the client doesn't have to seek to the end of the
+ * file to get the headers, but it requires copying all sample data
+ * out of the temp file at EOS, which can be expensive. Downstream does
+ * not need to be seekable, because of the use of the temp file.
+ *
+ */
+
#ifndef GST_REMOVE_DEPRECATED
enum
{
return seekable;
}
+static void
+gst_qt_mux_prepare_moov_recovery (GstQTMux * qtmux)
+{
+ GSList *walk;
+ gboolean fail = FALSE;
+ AtomFTYP *ftyp = NULL;
+ GstBuffer *prefix = NULL;
+
+ GST_DEBUG_OBJECT (qtmux, "Openning moov recovery file: %s",
+ qtmux->moov_recov_file_path);
+
+ qtmux->moov_recov_file = g_fopen (qtmux->moov_recov_file_path, "wb+");
+ if (qtmux->moov_recov_file == NULL) {
+ GST_WARNING_OBJECT (qtmux, "Failed to open moov recovery file in %s",
+ qtmux->moov_recov_file_path);
+ return;
+ }
+
+ gst_qt_mux_prepare_ftyp (qtmux, &ftyp, &prefix);
+
+ if (!atoms_recov_write_headers (qtmux->moov_recov_file, ftyp, prefix,
+ qtmux->moov, qtmux->timescale, g_slist_length (qtmux->sinkpads))) {
+ GST_WARNING_OBJECT (qtmux, "Failed to write moov recovery file " "headers");
+ goto fail;
+ }
+
+ atom_ftyp_free (ftyp);
+ if (prefix)
+ gst_buffer_unref (prefix);
+
+ for (walk = qtmux->sinkpads; walk && !fail; walk = g_slist_next (walk)) {
+ GstCollectData *cdata = (GstCollectData *) walk->data;
+ GstQTPad *qpad = (GstQTPad *) cdata;
+ /* write info for each stream */
+ fail = atoms_recov_write_trak_info (qtmux->moov_recov_file, qpad->trak);
+ if (fail) {
+ GST_WARNING_OBJECT (qtmux, "Failed to write trak info to recovery "
+ "file");
+ break;
+ }
+ }
+
+fail:
+ /* cleanup */
+ fclose (qtmux->moov_recov_file);
+ qtmux->moov_recov_file = NULL;
+ GST_WARNING_OBJECT (qtmux, "An error was detected while writing to "
+ "recover file, moov recovery won't work");
+}
static GstFlowReturn
gst_qt_mux_start_file (GstQTMux * qtmux)
{
+ GstQTMuxClass *qtmux_klass = (GstQTMuxClass *) (G_OBJECT_GET_CLASS (qtmux));
GstFlowReturn ret = GST_FLOW_OK;
GstCaps *caps;
GstSegment segment;
gst_pad_set_caps (qtmux->srcpad, caps);
gst_caps_unref (caps);
- /* if not streaming or doing fast-start, check if downstream is seekable */
- if (!qtmux->streamable) {
- if (!gst_qt_mux_downstream_is_seekable (qtmux)) {
- if (qtmux->fragment_duration == 0) {
- if (!qtmux->fast_start) {
- GST_ELEMENT_ERROR (qtmux, STREAM, MUX,
- ("Downstream is not seekable - will not be able to create a playable file"),
- (NULL));
- return GST_FLOW_ERROR;
- }
- } else {
+ /* Default is 'normal' mode */
+ qtmux->mux_mode = GST_QT_MUX_MODE_MOOV_AT_END;
+
+ /* Require a sensible fragment duration when muxing
+ * using the ISML muxer */
+ if (qtmux_klass->format == GST_QT_MUX_FORMAT_ISML &&
+ qtmux->fragment_duration == 0)
+ goto invalid_isml;
+
+ if (qtmux->fragment_duration > 0) {
+ if (qtmux->streamable)
+ qtmux->mux_mode = GST_QT_MUX_MODE_FRAGMENTED_STREAMABLE;
+ else
+ qtmux->mux_mode = GST_QT_MUX_MODE_FRAGMENTED;
+ } else if (qtmux->fast_start) {
+ qtmux->mux_mode = GST_QT_MUX_MODE_FAST_START;
+ }
+
+ switch (qtmux->mux_mode) {
+ case GST_QT_MUX_MODE_MOOV_AT_END:
+ /* We have to be able to seek to rewrite the mdat header, or any
+ * moov atom we write will not be visible in the file, because an
+ * MDAT with 0 as the size covers the rest of the file. A file
+ * with no moov is not playable, so error out now. */
+ if (!gst_qt_mux_downstream_is_seekable (qtmux)) {
+ GST_ELEMENT_ERROR (qtmux, STREAM, MUX,
+ ("Downstream is not seekable - will not be able to create a playable file"),
+ (NULL));
+ return GST_FLOW_ERROR;
+ }
+ break;
+ case GST_QT_MUX_MODE_FAST_START:
+ case GST_QT_MUX_MODE_FRAGMENTED_STREAMABLE:
+ break; /* Don't need seekability, ignore */
+ case GST_QT_MUX_MODE_FRAGMENTED:
+ if (!gst_qt_mux_downstream_is_seekable (qtmux)) {
GST_WARNING_OBJECT (qtmux, "downstream is not seekable, but "
"streamable=false. Will ignore that and create streamable output "
"instead");
qtmux->streamable = TRUE;
g_object_notify (G_OBJECT (qtmux), "streamable");
}
- }
+ break;
}
/* let downstream know we think in BYTES and expect to do seeking later on */
/* initialize our moov recovery file */
GST_OBJECT_LOCK (qtmux);
if (qtmux->moov_recov_file_path) {
- GST_DEBUG_OBJECT (qtmux, "Openning moov recovery file: %s",
- qtmux->moov_recov_file_path);
- qtmux->moov_recov_file = g_fopen (qtmux->moov_recov_file_path, "wb+");
- if (qtmux->moov_recov_file == NULL) {
- GST_WARNING_OBJECT (qtmux, "Failed to open moov recovery file in %s",
- qtmux->moov_recov_file_path);
- } else {
- GSList *walk;
- gboolean fail = FALSE;
- AtomFTYP *ftyp = NULL;
- GstBuffer *prefix = NULL;
-
- gst_qt_mux_prepare_ftyp (qtmux, &ftyp, &prefix);
-
- if (!atoms_recov_write_headers (qtmux->moov_recov_file, ftyp, prefix,
- qtmux->moov, qtmux->timescale,
- g_slist_length (qtmux->sinkpads))) {
- GST_WARNING_OBJECT (qtmux, "Failed to write moov recovery file "
- "headers");
- fail = TRUE;
- }
-
- atom_ftyp_free (ftyp);
- if (prefix)
- gst_buffer_unref (prefix);
-
- for (walk = qtmux->sinkpads; walk && !fail; walk = g_slist_next (walk)) {
- GstCollectData *cdata = (GstCollectData *) walk->data;
- GstQTPad *qpad = (GstQTPad *) cdata;
- /* write info for each stream */
- fail = atoms_recov_write_trak_info (qtmux->moov_recov_file, qpad->trak);
- if (fail) {
- GST_WARNING_OBJECT (qtmux, "Failed to write trak info to recovery "
- "file");
- }
- }
- if (fail) {
- /* cleanup */
- fclose (qtmux->moov_recov_file);
- qtmux->moov_recov_file = NULL;
- GST_WARNING_OBJECT (qtmux, "An error was detected while writing to "
- "recover file, moov recovery won't work");
- }
- }
+ gst_qt_mux_prepare_moov_recovery (qtmux);
}
GST_OBJECT_UNLOCK (qtmux);
- /*
+ /*
* send mdat header if already needed, and mark position for later update.
* We don't send ftyp now if we are on fast start mode, because we can
* better fine tune using the information we gather to create the whole moov
* atom.
*/
- if (qtmux->fast_start) {
- GST_OBJECT_LOCK (qtmux);
- qtmux->fast_start_file = g_fopen (qtmux->fast_start_file_path, "wb+");
- if (!qtmux->fast_start_file)
- goto open_failed;
- GST_OBJECT_UNLOCK (qtmux);
-
- /* send a dummy buffer for preroll */
- ret = gst_qt_mux_send_buffer (qtmux, gst_buffer_new (), NULL, FALSE);
- if (ret != GST_FLOW_OK)
- goto exit;
-
- } else {
- ret = gst_qt_mux_prepare_and_send_ftyp (qtmux);
- if (ret != GST_FLOW_OK) {
- goto exit;
- }
-
- /* well, it's moov pos if fragmented ... */
- qtmux->mdat_pos = qtmux->header_size;
+ switch (qtmux->mux_mode) {
+ case GST_QT_MUX_MODE_MOOV_AT_END:
+ ret = gst_qt_mux_prepare_and_send_ftyp (qtmux);
+ if (ret != GST_FLOW_OK)
+ break;
- if (qtmux->fragment_duration) {
+ /* store the mdat position for rewriting later ... */
+ qtmux->mdat_pos = qtmux->header_size;
+ /* extended atom in case we go over 4GB while writing and need
+ * the full 64-bit atom */
+ ret = gst_qt_mux_send_mdat_header (qtmux, &qtmux->header_size, 0, TRUE);
+ break;
+ case GST_QT_MUX_MODE_FAST_START:
+ GST_OBJECT_LOCK (qtmux);
+ qtmux->fast_start_file = g_fopen (qtmux->fast_start_file_path, "wb+");
+ if (!qtmux->fast_start_file)
+ goto open_failed;
+ GST_OBJECT_UNLOCK (qtmux);
+ /* send a dummy buffer for preroll */
+ ret = gst_qt_mux_send_buffer (qtmux, gst_buffer_new (), NULL, FALSE);
+ break;
+ case GST_QT_MUX_MODE_FRAGMENTED:
+ case GST_QT_MUX_MODE_FRAGMENTED_STREAMABLE:
+ ret = gst_qt_mux_prepare_and_send_ftyp (qtmux);
+ if (ret != GST_FLOW_OK)
+ break;
+ /* well, it's moov pos if fragmented ... */
+ qtmux->mdat_pos = qtmux->header_size;
GST_DEBUG_OBJECT (qtmux, "fragment duration %d ms, writing headers",
qtmux->fragment_duration);
/* also used as snapshot marker to indicate fragmented file */
ret =
gst_qt_mux_send_extra_atoms (qtmux, TRUE, &qtmux->header_size, FALSE);
if (ret != GST_FLOW_OK)
- return ret;
- /* prepare index */
- if (!qtmux->streamable)
+ break;
+ /* prepare index if not streamable */
+ if (qtmux->mux_mode == GST_QT_MUX_MODE_FRAGMENTED)
qtmux->mfra = atom_mfra_new (qtmux->context);
- } else {
- /* extended to ensure some spare space */
- ret = gst_qt_mux_send_mdat_header (qtmux, &qtmux->header_size, 0, TRUE);
- }
+ break;
}
-exit:
return ret;
-
/* ERRORS */
+invalid_isml:
+ {
+ GST_ELEMENT_ERROR (qtmux, STREAM, MUX,
+ ("Cannot create an ISML file with 0 fragment duration"), (NULL));
+ return GST_FLOW_ERROR;
+ }
+
open_failed:
{
GST_ELEMENT_ERROR (qtmux, RESOURCE, OPEN_READ_WRITE,
- (("Could not open temporary file \"%s\""), qtmux->fast_start_file_path),
- GST_ERROR_SYSTEM);
+ (("Could not open temporary file \"%s\""),
+ qtmux->fast_start_file_path), GST_ERROR_SYSTEM);
GST_OBJECT_UNLOCK (qtmux);
return GST_FLOW_ERROR;
}
}
}
- if (qtmux->fragment_sequence) {
- GstSegment segment;
-
- if (qtmux->mfra) {
+ switch (qtmux->mux_mode) {
+ case GST_QT_MUX_MODE_FRAGMENTED_STREAMABLE:
+ {
+ /* Streamable mode; no need to write duration or MFRA */
+ GST_DEBUG_OBJECT (qtmux, "streamable file; nothing to stop");
+ return GST_FLOW_OK;
+ }
+ case GST_QT_MUX_MODE_FRAGMENTED:
+ {
+ GstSegment segment;
guint8 *data = NULL;
GstBuffer *buf;
ret = gst_qt_mux_send_buffer (qtmux, buf, NULL, FALSE);
if (ret != GST_FLOW_OK)
return ret;
- } else {
- /* must have been streamable; no need to write duration */
- GST_DEBUG_OBJECT (qtmux, "streamable file; nothing to stop");
- return GST_FLOW_OK;
- }
- timescale = qtmux->timescale;
- /* only mvex duration is updated,
- * mvhd should be consistent with empty moov
- * (but TODO maybe some clients do not handle that well ?) */
- qtmux->moov->mvex.mehd.fragment_duration =
- gst_util_uint64_scale (first_ts, timescale, GST_SECOND);
- GST_DEBUG_OBJECT (qtmux, "rewriting moov with mvex duration %"
- GST_TIME_FORMAT, GST_TIME_ARGS (first_ts));
- /* seek and rewrite the header */
- gst_segment_init (&segment, GST_FORMAT_BYTES);
- segment.start = qtmux->mdat_pos;
- gst_pad_push_event (qtmux->srcpad, gst_event_new_segment (&segment));
- /* no need to seek back */
- return gst_qt_mux_send_moov (qtmux, NULL, FALSE);
+ timescale = qtmux->timescale;
+ /* only mvex duration is updated,
+ * mvhd should be consistent with empty moov
+ * (but TODO maybe some clients do not handle that well ?) */
+ qtmux->moov->mvex.mehd.fragment_duration =
+ gst_util_uint64_scale (first_ts, timescale, GST_SECOND);
+ GST_DEBUG_OBJECT (qtmux, "rewriting moov with mvex duration %"
+ GST_TIME_FORMAT, GST_TIME_ARGS (first_ts));
+ /* seek and rewrite the header */
+ gst_segment_init (&segment, GST_FORMAT_BYTES);
+ segment.start = qtmux->mdat_pos;
+ gst_pad_push_event (qtmux->srcpad, gst_event_new_segment (&segment));
+ /* no need to seek back */
+ return gst_qt_mux_send_moov (qtmux, NULL, FALSE);
+ }
+ default:
+ break;
}
+ /* Moov-at-end or fast-start mode from here down */
gst_qt_mux_configure_moov (qtmux, ×cale);
-
- /* check for late streams */
+ /* check for late streams. First, find the earliest start time */
first_ts = GST_CLOCK_TIME_NONE;
for (walk = qtmux->collect->data; walk; walk = g_slist_next (walk)) {
GstCollectData *cdata = (GstCollectData *) walk->data;
/* tags into file metadata */
gst_qt_mux_setup_metadata (qtmux);
-
large_file = (qtmux->mdat_size > MDAT_LARGE_FILE_LIMIT);
+
/* if faststart, update the offset of the atoms in the movie with the offset
* that the movie headers before mdat will cause.
* Also, send the ftyp */
- if (qtmux->fast_start_file) {
+ if (qtmux->mux_mode == GST_QT_MUX_MODE_FAST_START) {
GstFlowReturn flow_ret;
offset = size = 0;
} else {
offset = qtmux->header_size;
}
+
+ /* Now that we know the size of moov + extra atoms, we can adjust
+ * the chunk offsets stored into the moov */
atom_moov_chunks_add_offset (qtmux->moov, offset);
- /* moov */
+ /* write out moov and extra atoms */
/* note: as of this point, we no longer care about tracking written data size,
* since there is no more use for it anyway */
ret = gst_qt_mux_send_moov (qtmux, NULL, FALSE);
if (ret != GST_FLOW_OK)
return ret;
- /* if needed, send mdat atom and move buffered data into it */
- if (qtmux->fast_start_file) {
- /* mdat_size = accumulated (buffered data) */
- ret = gst_qt_mux_send_mdat_header (qtmux, NULL, qtmux->mdat_size,
- large_file);
- if (ret != GST_FLOW_OK)
- return ret;
- ret = gst_qt_mux_send_buffered_data (qtmux, NULL);
- if (ret != GST_FLOW_OK)
- return ret;
- } else if (!qtmux->streamable) {
- /* mdat needs update iff not using faststart */
- GST_DEBUG_OBJECT (qtmux, "updating mdat size");
- ret = gst_qt_mux_update_mdat_size (qtmux, qtmux->mdat_pos,
- qtmux->mdat_size, NULL);
- /* note; no seeking back to the end of file is done,
- * since we no longer write anything anyway */
+ switch (qtmux->mux_mode) {
+ case GST_QT_MUX_MODE_MOOV_AT_END:
+ {
+ /* mdat needs update iff not using faststart */
+ GST_DEBUG_OBJECT (qtmux, "updating mdat size");
+ ret = gst_qt_mux_update_mdat_size (qtmux, qtmux->mdat_pos,
+ qtmux->mdat_size, NULL);
+ /* note; no seeking back to the end of file is done,
+ * since we no longer write anything anyway */
+ break;
+ }
+ case GST_QT_MUX_MODE_FAST_START:
+ {
+ /* send mdat atom and move buffered data into it */
+ /* mdat_size = accumulated (buffered data) */
+ ret = gst_qt_mux_send_mdat_header (qtmux, NULL, qtmux->mdat_size,
+ large_file);
+ if (ret != GST_FLOW_OK)
+ return ret;
+ ret = gst_qt_mux_send_buffered_data (qtmux, NULL);
+ if (ret != GST_FLOW_OK)
+ return ret;
+ break;
+ }
+ default:
+ g_assert_not_reached ();
}
return ret;
}
}
- if (qtmux->fragment_sequence) {
- /* ensure that always sync samples are marked as such */
- ret = gst_qt_mux_pad_fragment_add_buffer (qtmux, pad, buffer,
- is_last_buffer, nsamples, last_dts, (gint32) scaled_duration,
- sample_size, !pad->sync || sync, pts_offset);
- } else {
- atom_trak_add_samples (pad->trak, nsamples, (gint32) scaled_duration,
- sample_size, chunk_offset, sync, pts_offset);
- ret = gst_qt_mux_send_buffer (qtmux, buffer, &qtmux->mdat_size, TRUE);
+ switch (qtmux->mux_mode) {
+ case GST_QT_MUX_MODE_MOOV_AT_END:
+ case GST_QT_MUX_MODE_FAST_START:
+
+ atom_trak_add_samples (pad->trak, nsamples, (gint32) scaled_duration,
+ sample_size, chunk_offset, sync, pts_offset);
+ ret = gst_qt_mux_send_buffer (qtmux, buffer, &qtmux->mdat_size, TRUE);
+ break;
+ case GST_QT_MUX_MODE_FRAGMENTED:
+ case GST_QT_MUX_MODE_FRAGMENTED_STREAMABLE:
+ /* ensure that always sync samples are marked as such */
+ ret = gst_qt_mux_pad_fragment_add_buffer (qtmux, pad, buffer,
+ is_last_buffer, nsamples, last_dts, (gint32) scaled_duration,
+ sample_size, !pad->sync || sync, pts_offset);
+ break;
}
return ret;
projects / platform / upstream / gstreamer.git / commitdiff