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avcodec/mpeg12enc: avoid floats in the aspect ratio info setup code

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This fixes potential rounding issues with floats, and also
fixes a division by 0

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2014-05-16 18:47:42 +02:00
parent b217e1b057
commit 7ebf90ff47
1 changed files with 8 additions and 8 deletions
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16
libavcodec/mpeg12enc.c
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@ -240,11 +240,11 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
unsigned int vbv_buffer_size, fps, v;
int i, constraint_parameter_flag;
uint64_t time_code;
float best_aspect_error = 1E10;
float aspect_ratio = av_q2d(s->avctx->sample_aspect_ratio);
int64_t best_aspect_error = INT64_MAX;
AVRational aspect_ratio = s->avctx->sample_aspect_ratio;
if (aspect_ratio == 0.0)
aspect_ratio = 1.0; // pixel aspect 1.1 (VGA)
if (aspect_ratio.num == 0 || aspect_ratio.den == 0)
aspect_ratio = (AVRational){1,1}; // pixel aspect 1.1 (VGA)
if (s->current_picture.f->key_frame) {
AVRational framerate = ff_mpeg12_frame_rate_tab[s->frame_rate_index];
@ -256,15 +256,15 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)
put_sbits(&s->pb, 12, s->height & 0xFFF);
for (i = 1; i < 15; i++) {
float error = aspect_ratio;
int64_t error = aspect_ratio.num * (1LL<<32) / aspect_ratio.den;
if (s->codec_id == AV_CODEC_ID_MPEG1VIDEO || i <= 1)
error -= 1.0 / ff_mpeg1_aspect[i];
error -= (1LL<<32) / ff_mpeg1_aspect[i];
else
error -= av_q2d(ff_mpeg2_aspect[i]) * s->height / s->width;
error -= (1LL<<32)*ff_mpeg2_aspect[i].num * s->height / s->width / ff_mpeg2_aspect[i].den;
error = FFABS(error);
if (error <= best_aspect_error) {
if (error - 2 <= best_aspect_error) {
best_aspect_error = error;
s->aspect_ratio_info = i;
}