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lavf: round estimated average fps to a "standard" fps.

This commit is contained in:
Anton Khirnov 2012-07-27 14:04:07 +02:00
parent fe1c1198e6
commit f66eeff1c8
1 changed files with 18 additions and 0 deletions
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18
libavformat/utils.c
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@ -2485,10 +2485,28 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
if (!st->avg_frame_rate.num && st->info->fps_last_dts != st->info->fps_first_dts) {
int64_t delta_dts = st->info->fps_last_dts - st->info->fps_first_dts;
int delta_packets = st->info->fps_last_dts_idx - st->info->fps_first_dts_idx;
int best_fps = 0;
double best_error = 0.01;
av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
delta_packets*(int64_t)st->time_base.den,
delta_dts*(int64_t)st->time_base.num, 60000);
/* round guessed framerate to a "standard" framerate if it's
* within 1% of the original estimate*/
for (j = 1; j < MAX_STD_TIMEBASES; j++) {
AVRational std_fps = (AVRational){get_std_framerate(j), 12*1001};
double error = fabs(av_q2d(st->avg_frame_rate) / av_q2d(std_fps) - 1);
if (error < best_error) {
best_error = error;
best_fps = std_fps.num;
}
}
if (best_fps) {
av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
best_fps, 12*1001, INT_MAX);
}
}
// the check for tb_unreliable() is not completely correct, since this is not about handling
// a unreliable/inexact time base, but a time base that is finer than necessary, as e.g.