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mpeg2enc: support and use frame_rate_ext when needed

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-10-04 15:25:30 +02:00
parent 489d8a79a6
commit e214306775
2 changed files with 25 additions and 11 deletions
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35
libavcodec/mpeg12enc.c
View File

@ -108,21 +108,34 @@ static void init_uni_ac_vlc(RLTable *rl, uint8_t *uni_ac_vlc_len){
static int find_frame_rate_index(MpegEncContext *s){
int i;
int64_t dmin= INT64_MAX;
int64_t d;
AVRational bestq= (AVRational){0, 0};
AVRational ext;
AVRational target = av_inv_q(s->avctx->time_base);
for(i=1;i<14;i++) {
int64_t n0= 1001LL/avpriv_frame_rate_tab[i].den*avpriv_frame_rate_tab[i].num*s->avctx->time_base.num;
int64_t n1= 1001LL*s->avctx->time_base.den;
if(s->avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL && i>=9) break;
d = FFABS(n0 - n1);
if(d < dmin){
dmin=d;
s->frame_rate_index= i;
for (ext.num=1; ext.num <= 4; ext.num++) {
for (ext.den=1; ext.den <= 32; ext.den++) {
AVRational q = av_mul_q(ext, avpriv_frame_rate_tab[i]);
if(s->codec_id != AV_CODEC_ID_MPEG2VIDEO && (ext.den!=1 || ext.num!=1))
continue;
if(av_gcd(ext.den, ext.num) != 1)
continue;
if( bestq.num==0
|| av_nearer_q(target, bestq, q) < 0
|| ext.num==1 && ext.den==1 && av_nearer_q(target, bestq, q) == 0){
bestq = q;
s->frame_rate_index= i;
s->mpeg2_frame_rate_ext.num = ext.num;
s->mpeg2_frame_rate_ext.den = ext.den;
}
}
}
}
if(dmin)
if(av_cmp_q(target, bestq))
return -1;
else
return 0;
@ -286,8 +299,8 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
put_bits(&s->pb, 1, 1); //marker
put_bits(&s->pb, 8, vbv_buffer_size >>10); //vbv buffer ext
put_bits(&s->pb, 1, s->low_delay);
put_bits(&s->pb, 2, 0); // frame_rate_ext_n
put_bits(&s->pb, 5, 0); // frame_rate_ext_d
put_bits(&s->pb, 2, s->mpeg2_frame_rate_ext.num-1); // frame_rate_ext_n
put_bits(&s->pb, 5, s->mpeg2_frame_rate_ext.den-1); // frame_rate_ext_d
}
put_header(s, GOP_START_CODE);

1
libavcodec/mpegvideo.h
View File

@ -347,6 +347,7 @@ typedef struct MpegEncContext {
int last_non_b_pict_type; ///< used for mpeg4 gmc b-frames & ratecontrol
int dropable;
int frame_rate_index;
AVRational mpeg2_frame_rate_ext;
int last_lambda_for[5]; ///< last lambda for a specific pict type
int skipdct; ///< skip dct and code zero residual