generic-library/ffmpeg
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Use a MD5 hash of some frames to write the segment uid

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Originally committed as revision 10348 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2007-09-05 00:24:29 +00:00
parent f095a17423
commit 541d443c03
1 changed files with 21 additions and 0 deletions
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21
libavformat/matroskaenc.c
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@ -20,6 +20,7 @@
*/
#include "avformat.h"
#include "md5.h"
#include "riff.h"
#include "xiph.h"
#include "matroska.h"
@ -53,6 +54,7 @@ typedef struct {
typedef struct MatroskaMuxContext {
offset_t segment;
offset_t segment_offset;
offset_t segment_uid;
offset_t cluster;
offset_t cluster_pos; ///< file offset of the current cluster
uint64_t cluster_pts;
@ -61,6 +63,8 @@ typedef struct MatroskaMuxContext {
mkv_seekhead *main_seekhead;
mkv_seekhead *cluster_seekhead;
mkv_cues *cues;
struct AVMD5 *md5_ctx;
} MatroskaMuxContext;
static void put_ebml_id(ByteIOContext *pb, unsigned int id)
@ -547,6 +551,9 @@ static int mkv_write_header(AVFormatContext *s)
ByteIOContext *pb = &s->pb;
offset_t ebml_header, segment_info;
mkv->md5_ctx = av_mallocz(av_md5_size);
av_md5_init(mkv->md5_ctx);
ebml_header = start_ebml_master(pb, EBML_ID_HEADER);
put_ebml_uint (pb, EBML_ID_EBMLVERSION , 1);
put_ebml_uint (pb, EBML_ID_EBMLREADVERSION , 1);
@ -577,6 +584,10 @@ static int mkv_write_header(AVFormatContext *s)
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
put_ebml_string(pb, MATROSKA_ID_MUXINGAPP , LIBAVFORMAT_IDENT);
put_ebml_string(pb, MATROSKA_ID_WRITINGAPP, LIBAVFORMAT_IDENT);
// reserve space to write the segment UID later
mkv->segment_uid = url_ftell(pb);
put_ebml_void(pb, 19);
}
// reserve space for the duration
@ -637,6 +648,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, pkt->pts);
mkv->cluster_pts = pkt->pts;
av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
}
if (codec->codec_type != CODEC_TYPE_SUBTITLE) {
@ -677,9 +689,18 @@ static int mkv_write_trailer(AVFormatContext *s)
currentpos = url_ftell(pb);
url_fseek(pb, mkv->duration_offset, SEEK_SET);
put_ebml_float(pb, MATROSKA_ID_DURATION, mkv->duration);
// write the md5sum of some frames as the segment UID
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
uint8_t segment_uid[16];
av_md5_final(mkv->md5_ctx, segment_uid);
url_fseek(pb, mkv->segment_uid, SEEK_SET);
put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
}
url_fseek(pb, currentpos, SEEK_SET);
end_ebml_master(pb, mkv->segment);
av_free(mkv->md5_ctx);
return 0;
}