generic-library/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

matroskaenc: Use av_get_random_seed -> lfg for segment UID

Browse Source 
Originally committed as revision 23476 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2010-06-04 22:41:03 +00:00
parent 4a6bef1f36
commit 1f4280e744
1 changed files with 11 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
libavformat/matroskaenc.c
View File

@ -26,7 +26,8 @@
#include "avc.h"
#include "flacenc.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/md5.h"
#include "libavutil/random_seed.h"
#include "libavutil/lfg.h"
#include "libavcodec/xiph.h"
#include "libavcodec/mpeg4audio.h"
@ -73,7 +74,6 @@ typedef struct MatroskaMuxContext {
ByteIOContext *dyn_bc;
ebml_master segment;
int64_t segment_offset;
int64_t segment_uid;
ebml_master cluster;
int64_t cluster_pos; ///< file offset of the current cluster
int64_t cluster_pts;
@ -84,7 +84,7 @@ typedef struct MatroskaMuxContext {
mkv_cues *cues;
mkv_track *tracks;
struct AVMD5 *md5_ctx;
AVLFG lfg;
unsigned int audio_buffer_size;
AVPacket cur_audio_pkt;
} MatroskaMuxContext;
@ -695,13 +695,13 @@ static int mkv_write_header(AVFormatContext *s)
ByteIOContext *pb = s->pb;
ebml_master ebml_header, segment_info;
AVMetadataTag *tag;
int ret;
int ret, i;
if (!strcmp(s->oformat->name, "webm")) mkv->mode = MODE_WEBM;
else mkv->mode = MODE_MATROSKAv2;
mkv->md5_ctx = av_mallocz(av_md5_size);
av_md5_init(mkv->md5_ctx);
av_lfg_init(&mkv->lfg, av_get_random_seed());
mkv->tracks = av_mallocz(s->nb_streams * sizeof(*mkv->tracks));
ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
@ -735,12 +735,13 @@ static int mkv_write_header(AVFormatContext *s)
if ((tag = av_metadata_get(s->metadata, "title", NULL, 0)))
put_ebml_string(pb, MATROSKA_ID_TITLE, tag->value);
if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
uint32_t segment_uid[4];
for (i = 0; i < 4; i++)
segment_uid[i] = av_lfg_get(&mkv->lfg);
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);
put_ebml_binary(pb, MATROSKA_ID_SEGMENTUID, segment_uid, 16);
}
// reserve space for the duration
@ -912,7 +913,6 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
mkv->cluster = start_ebml_master(pb, MATROSKA_ID_CLUSTER, 0);
put_ebml_uint(pb, MATROSKA_ID_CLUSTERTIMECODE, FFMAX(0, ts));
mkv->cluster_pts = FFMAX(0, ts);
av_md5_update(mkv->md5_ctx, pkt->data, FFMIN(200, pkt->size));
}
if (codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
@ -1033,18 +1033,10 @@ static int mkv_write_trailer(AVFormatContext *s)
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);
av_free(mkv->tracks);
av_destruct_packet(&mkv->cur_audio_pkt);
put_flush_packet(pb);