diff --git a/libavcodec/h264.c b/libavcodec/h264.c index b7978936b8..8b95003f75 100644 --- a/libavcodec/h264.c +++ b/libavcodec/h264.c @@ -803,7 +803,7 @@ static void decode_postinit(H264Context *h, int setup_finished) /* Derive top_field_first from field pocs. */ cur->f->top_field_first = cur->field_poc[0] < cur->field_poc[1]; } else { - if (cur->f->interlaced_frame || h->sps.pic_struct_present_flag) { + if (h->sps.pic_struct_present_flag) { /* Use picture timing SEI information. Even if it is a * information of a past frame, better than nothing. */ if (h->sei_pic_struct == SEI_PIC_STRUCT_TOP_BOTTOM || @@ -811,6 +811,10 @@ static void decode_postinit(H264Context *h, int setup_finished) cur->f->top_field_first = 1; else cur->f->top_field_first = 0; + } else if (cur->f->interlaced_frame) { + /* Default to top field first when pic_struct_present_flag + * is not set but interlaced frame detected */ + cur->f->top_field_first = 1; } else { /* Most likely progressive */ cur->f->top_field_first = 0;