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avformat/mp3dec: split position sync code out

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Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2015-07-19 19:31:08 +02:00
parent ea8785ceda
commit 4df66c7cd6
1 changed files with 48 additions and 40 deletions
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88
libavformat/mp3dec.c
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@ -437,6 +437,50 @@ static int check(AVIOContext *pb, int64_t pos)
return sd.frame_size; return sd.frame_size;
} }
static int64_t sync(AVFormatContext *s, int64_t target_pos, int flags)
{
int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
int64_t best_pos;
int best_score, i, j;
int64_t ret;
avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
ret = avio_seek(s->pb, target_pos, SEEK_SET);
if (ret < 0)
return ret;
#define MIN_VALID 3
best_pos = target_pos;
best_score = 999;
for(i=0; i<SEEK_WINDOW; i++) {
int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
int64_t candidate = -1;
int score = 999;
if (pos < 0)
continue;
for(j=0; j<MIN_VALID; j++) {
ret = check(s->pb, pos);
if(ret < 0)
break;
if ((target_pos - pos)*dir <= 0 && abs(MIN_VALID/2-j) < score) {
candidate = pos;
score = abs(MIN_VALID/2-j);
}
pos += ret;
}
if (best_score > score && j == MIN_VALID) {
best_pos = candidate;
best_score = score;
if(score == 0)
break;
}
}
return avio_seek(s->pb, best_pos, SEEK_SET);
}
static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp, static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
int flags) int flags)
{ {
@ -444,10 +488,8 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
AVIndexEntry *ie, ie1; AVIndexEntry *ie, ie1;
AVStream *st = s->streams[0]; AVStream *st = s->streams[0];
int64_t ret = av_index_search_timestamp(st, timestamp, flags); int64_t ret = av_index_search_timestamp(st, timestamp, flags);
int i, j;
int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
int64_t best_pos; int64_t best_pos;
int best_score; int i;
if (mp3->usetoc == 2) if (mp3->usetoc == 2)
return -1; // generic index code return -1; // generic index code
@ -470,43 +512,9 @@ static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
return -1; return -1;
} }
avio_seek(s->pb, FFMAX(ie->pos - SEEK_WINDOW, 0), SEEK_SET); best_pos = sync(s, ie->pos, flags);
ret = avio_seek(s->pb, ie->pos, SEEK_SET); if (best_pos < 0)
if (ret < 0) return best_pos;
return ret;
#define MIN_VALID 3
best_pos = ie->pos;
best_score = 999;
for(i=0; i<SEEK_WINDOW; i++) {
int64_t pos = ie->pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
int64_t candidate = -1;
int score = 999;
if (pos < 0)
continue;
for(j=0; j<MIN_VALID; j++) {
ret = check(s->pb, pos);
if(ret < 0)
break;
if ((ie->pos - pos)*dir <= 0 && abs(MIN_VALID/2-j) < score) {
candidate = pos;
score = abs(MIN_VALID/2-j);
}
pos += ret;
}
if (best_score > score && j == MIN_VALID) {
best_pos = candidate;
best_score = score;
if(score == 0)
break;
}
}
ret = avio_seek(s->pb, best_pos, SEEK_SET);
if (ret < 0)
return ret;
if (mp3->is_cbr && ie == &ie1) { if (mp3->is_cbr && ie == &ie1) {
int frame_duration = av_rescale(st->duration, 1, mp3->frames); int frame_duration = av_rescale(st->duration, 1, mp3->frames);