sar = dec_ctx->sample_aspect_ratio;
ost->st->sample_aspect_ratio = enc_ctx->sample_aspect_ratio = sar;
ost->st->avg_frame_rate = ist->st->avg_frame_rate;
sar = dec_ctx->sample_aspect_ratio;
ost->st->sample_aspect_ratio = enc_ctx->sample_aspect_ratio = sar;
ost->st->avg_frame_rate = ist->st->avg_frame_rate;