[FFmpeg-cvslog] avformat/matroskaenc: Write level 1 elements in one go
Andreas Rheinhardt
git at videolan.org
Mon Mar 30 09:01:38 EEST 2020
ffmpeg | branch: release/4.2 | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Mon Dec 30 15:59:02 2019 +0100| [477275795865f074e60635d813a7b765284ca948] | committer: Andreas Rheinhardt
avformat/matroskaenc: Write level 1 elements in one go
Up until now, writing level 1 elements proceeded as follows: First, the
element id was written to the ordinary output AVIOContext and a dynamic
buffer was opened for the content of the level 1 element in
start_ebml_master_crc32(). Then this buffer was actually used and after it
was closed (in end_ebml_master_crc32()), the size field corresponding to
the buffer's size was written, after which the actual data was written.
This commit changes this: Nothing is written to the main AVIOContext any
more in start_ebml_master_crc32(). end_ebml_master_crc32() now writes
both the id, the length field as well as the data. This is benefical for
streaming, because a client that receives just a Cluster ID and nothing
more might infer that this is EOF; in certain usecases there is also the
danger of a client receiving the Cluster without the actual Cluster ID
at the beginning.
Addresses #8578.
(cherry picked from commit d9c21ec)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=477275795865f074e60635d813a7b765284ca948
---
libavformat/matroskaenc.c | 63 +++++++++++++++++++++++++----------------------
1 file changed, 34 insertions(+), 29 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index cef504fa05..2e63b90b28 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -331,26 +331,26 @@ static void end_ebml_master(AVIOContext *pb, ebml_master master)
avio_seek(pb, pos, SEEK_SET);
}
-static int start_ebml_master_crc32(AVIOContext *pb, AVIOContext **dyn_cp, MatroskaMuxContext *mkv,
- uint32_t elementid)
+static int start_ebml_master_crc32(AVIOContext **dyn_cp, MatroskaMuxContext *mkv)
{
int ret;
if ((ret = avio_open_dyn_buf(dyn_cp)) < 0)
return ret;
- put_ebml_id(pb, elementid);
if (mkv->write_crc)
put_ebml_void(*dyn_cp, 6); /* Reserve space for CRC32 so position/size calculations using avio_tell() take it into account */
return 0;
}
-static void end_ebml_master_crc32(AVIOContext *pb, AVIOContext **dyn_cp, MatroskaMuxContext *mkv)
+static void end_ebml_master_crc32(AVIOContext *pb, AVIOContext **dyn_cp,
+ MatroskaMuxContext *mkv, uint32_t id)
{
uint8_t *buf, crc[4];
int size, skip = 0;
+ put_ebml_id(pb, id);
size = avio_close_dyn_buf(*dyn_cp, &buf);
put_ebml_num(pb, size, 0);
if (mkv->write_crc) {
@@ -368,13 +368,14 @@ static void end_ebml_master_crc32(AVIOContext *pb, AVIOContext **dyn_cp, Matrosk
* Complete ebml master without destroying the buffer, allowing for later updates
*/
static void end_ebml_master_crc32_preliminary(AVIOContext *pb, AVIOContext **dyn_cp, MatroskaMuxContext *mkv,
- int64_t *pos)
+ uint32_t id, int64_t *pos)
{
uint8_t *buf;
int size = avio_get_dyn_buf(*dyn_cp, &buf);
*pos = avio_tell(pb);
+ put_ebml_id(pb, id);
put_ebml_num(pb, size, 0);
avio_write(pb, buf, size);
}
@@ -500,7 +501,7 @@ static int64_t mkv_write_seekhead(AVIOContext *pb, MatroskaMuxContext *mkv)
}
}
- if (start_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_SEEKHEAD) < 0) {
+ if (start_ebml_master_crc32(&dyn_cp, mkv) < 0) {
currentpos = -1;
goto fail;
}
@@ -517,7 +518,7 @@ static int64_t mkv_write_seekhead(AVIOContext *pb, MatroskaMuxContext *mkv)
put_ebml_uint(dyn_cp, MATROSKA_ID_SEEKPOSITION, entry->segmentpos);
end_ebml_master(dyn_cp, seekentry);
}
- end_ebml_master_crc32(pb, &dyn_cp, mkv);
+ end_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_SEEKHEAD);
if (seekhead->reserved_size > 0) {
uint64_t remaining = seekhead->filepos + seekhead->reserved_size - avio_tell(pb);
@@ -574,7 +575,7 @@ static int64_t mkv_write_cues(AVFormatContext *s, mkv_cues *cues, mkv_track *tra
int i, j, ret;
currentpos = avio_tell(pb);
- ret = start_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_CUES);
+ ret = start_ebml_master_crc32(&dyn_cp, mkv);
if (ret < 0)
return ret;
@@ -620,7 +621,7 @@ static int64_t mkv_write_cues(AVFormatContext *s, mkv_cues *cues, mkv_track *tra
i += j - 1;
end_ebml_master(dyn_cp, cuepoint);
}
- end_ebml_master_crc32(pb, &dyn_cp, mkv);
+ end_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_CUES);
return currentpos;
}
@@ -1450,7 +1451,7 @@ static int mkv_write_tracks(AVFormatContext *s)
if (ret < 0)
return ret;
- ret = start_ebml_master_crc32(pb, &mkv->tracks_bc, mkv, MATROSKA_ID_TRACKS);
+ ret = start_ebml_master_crc32(&mkv->tracks_bc, mkv);
if (ret < 0)
return ret;
@@ -1465,9 +1466,10 @@ static int mkv_write_tracks(AVFormatContext *s)
}
if ((pb->seekable & AVIO_SEEKABLE_NORMAL) && !mkv->is_live)
- end_ebml_master_crc32_preliminary(pb, &mkv->tracks_bc, mkv, &mkv->tracks_pos);
+ end_ebml_master_crc32_preliminary(pb, &mkv->tracks_bc, mkv,
+ MATROSKA_ID_TRACKS, &mkv->tracks_pos);
else
- end_ebml_master_crc32(pb, &mkv->tracks_bc, mkv);
+ end_ebml_master_crc32(pb, &mkv->tracks_bc, mkv, MATROSKA_ID_TRACKS);
return 0;
}
@@ -1486,7 +1488,7 @@ static int mkv_write_chapters(AVFormatContext *s)
ret = mkv_add_seekhead_entry(mkv->seekhead, MATROSKA_ID_CHAPTERS, avio_tell(pb));
if (ret < 0) return ret;
- ret = start_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_CHAPTERS);
+ ret = start_ebml_master_crc32(&dyn_cp, mkv);
if (ret < 0) return ret;
editionentry = start_ebml_master(dyn_cp, MATROSKA_ID_EDITIONENTRY, 0);
@@ -1524,7 +1526,7 @@ static int mkv_write_chapters(AVFormatContext *s)
end_ebml_master(dyn_cp, chapteratom);
}
end_ebml_master(dyn_cp, editionentry);
- end_ebml_master_crc32(pb, &dyn_cp, mkv);
+ end_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_CHAPTERS);
mkv->wrote_chapters = 1;
return 0;
@@ -1576,7 +1578,7 @@ static int mkv_write_tag_targets(AVFormatContext *s, uint32_t elementid,
ret = mkv_add_seekhead_entry(mkv->seekhead, MATROSKA_ID_TAGS, avio_tell(s->pb));
if (ret < 0) return ret;
- start_ebml_master_crc32(s->pb, &mkv->tags_bc, mkv, MATROSKA_ID_TAGS);
+ start_ebml_master_crc32(&mkv->tags_bc, mkv);
}
pb = mkv->tags_bc;
@@ -1716,9 +1718,10 @@ static int mkv_write_tags(AVFormatContext *s)
if (mkv->tags_bc) {
if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) && !mkv->is_live)
- end_ebml_master_crc32_preliminary(s->pb, &mkv->tags_bc, mkv, &mkv->tags_pos);
+ end_ebml_master_crc32_preliminary(s->pb, &mkv->tags_bc, mkv,
+ MATROSKA_ID_TAGS, &mkv->tags_pos);
else
- end_ebml_master_crc32(s->pb, &mkv->tags_bc, mkv);
+ end_ebml_master_crc32(s->pb, &mkv->tags_bc, mkv, MATROSKA_ID_TAGS);
}
return 0;
}
@@ -1742,7 +1745,7 @@ static int mkv_write_attachments(AVFormatContext *s)
ret = mkv_add_seekhead_entry(mkv->seekhead, MATROSKA_ID_ATTACHMENTS, avio_tell(pb));
if (ret < 0) return ret;
- ret = start_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_ATTACHMENTS);
+ ret = start_ebml_master_crc32(&dyn_cp, mkv);
if (ret < 0) return ret;
for (i = 0; i < s->nb_streams; i++) {
@@ -1815,7 +1818,7 @@ static int mkv_write_attachments(AVFormatContext *s)
mkv->attachments->entries[mkv->attachments->num_entries].stream_idx = i;
mkv->attachments->entries[mkv->attachments->num_entries++].fileuid = fileuid;
}
- end_ebml_master_crc32(pb, &dyn_cp, mkv);
+ end_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_ATTACHMENTS);
return 0;
}
@@ -1901,7 +1904,7 @@ static int mkv_write_header(AVFormatContext *s)
ret = mkv_add_seekhead_entry(mkv->seekhead, MATROSKA_ID_INFO, avio_tell(pb));
if (ret < 0) goto fail;
- ret = start_ebml_master_crc32(pb, &mkv->info_bc, mkv, MATROSKA_ID_INFO);
+ ret = start_ebml_master_crc32(&mkv->info_bc, mkv);
if (ret < 0)
return ret;
pb = mkv->info_bc;
@@ -1960,9 +1963,10 @@ static int mkv_write_header(AVFormatContext *s)
}
}
if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) && !mkv->is_live)
- end_ebml_master_crc32_preliminary(s->pb, &mkv->info_bc, mkv, &mkv->info_pos);
+ end_ebml_master_crc32_preliminary(s->pb, &mkv->info_bc, mkv,
+ MATROSKA_ID_INFO, &mkv->info_pos);
else
- end_ebml_master_crc32(s->pb, &mkv->info_bc, mkv);
+ end_ebml_master_crc32(s->pb, &mkv->info_bc, mkv, MATROSKA_ID_INFO);
pb = s->pb;
// initialize stream_duration fields
@@ -2258,7 +2262,7 @@ static void mkv_start_new_cluster(AVFormatContext *s, AVPacket *pkt)
{
MatroskaMuxContext *mkv = s->priv_data;
- end_ebml_master_crc32(s->pb, &mkv->cluster_bc, mkv);
+ end_ebml_master_crc32(s->pb, &mkv->cluster_bc, mkv, MATROSKA_ID_CLUSTER);
mkv->cluster_pos = -1;
av_log(s, AV_LOG_DEBUG,
"Starting new cluster at offset %" PRIu64 " bytes, "
@@ -2403,7 +2407,7 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt, int add_
if (mkv->cluster_pos == -1) {
mkv->cluster_pos = avio_tell(s->pb);
- ret = start_ebml_master_crc32(s->pb, &mkv->cluster_bc, mkv, MATROSKA_ID_CLUSTER);
+ ret = start_ebml_master_crc32(&mkv->cluster_bc, mkv);
if (ret < 0)
return ret;
put_ebml_uint(mkv->cluster_bc, MATROSKA_ID_CLUSTERTIMECODE, FFMAX(0, ts));
@@ -2539,7 +2543,8 @@ static int mkv_write_flush_packet(AVFormatContext *s, AVPacket *pkt)
if (!pkt) {
if (mkv->cluster_pos != -1) {
- end_ebml_master_crc32(s->pb, &mkv->cluster_bc, mkv);
+ end_ebml_master_crc32(s->pb, &mkv->cluster_bc,
+ mkv, MATROSKA_ID_CLUSTER);
mkv->cluster_pos = -1;
av_log(s, AV_LOG_DEBUG,
"Flushing cluster at offset %" PRIu64 " bytes\n",
@@ -2570,7 +2575,7 @@ static int mkv_write_trailer(AVFormatContext *s)
}
if (mkv->cluster_bc) {
- end_ebml_master_crc32(pb, &mkv->cluster_bc, mkv);
+ end_ebml_master_crc32(pb, &mkv->cluster_bc, mkv, MATROSKA_ID_CLUSTER);
}
ret = mkv_write_chapters(s);
@@ -2619,11 +2624,11 @@ static int mkv_write_trailer(AVFormatContext *s)
avio_seek(mkv->info_bc, mkv->duration_offset, SEEK_SET);
put_ebml_float(mkv->info_bc, MATROSKA_ID_DURATION, mkv->duration);
avio_seek(pb, mkv->info_pos, SEEK_SET);
- end_ebml_master_crc32(pb, &mkv->info_bc, mkv);
+ end_ebml_master_crc32(pb, &mkv->info_bc, mkv, MATROSKA_ID_INFO);
// write tracks master
avio_seek(pb, mkv->tracks_pos, SEEK_SET);
- end_ebml_master_crc32(pb, &mkv->tracks_bc, mkv);
+ end_ebml_master_crc32(pb, &mkv->tracks_bc, mkv, MATROSKA_ID_TRACKS);
// update stream durations
if (!mkv->is_live && mkv->stream_durations) {
@@ -2652,7 +2657,7 @@ static int mkv_write_trailer(AVFormatContext *s)
}
if (mkv->tags_bc && !mkv->is_live) {
avio_seek(pb, mkv->tags_pos, SEEK_SET);
- end_ebml_master_crc32(pb, &mkv->tags_bc, mkv);
+ end_ebml_master_crc32(pb, &mkv->tags_bc, mkv, MATROSKA_ID_TAGS);
}
avio_seek(pb, currentpos, SEEK_SET);
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