[FFmpeg-cvslog] mpegdec: fix redundant dummy frames issue of interlaced clips

[Zhong Li]

ffmpeg | branch: master | Zhong Li <zhong.li at intel.com> | Sat Sep 30 11:22:57 2017 +0800| [fd7cb86468cc63b5bda203d74964584281318cda] | committer: Michael Niedermayer

mpegdec: fix redundant dummy frames issue of interlaced clips

It is to fix https://trac.ffmpeg.org/ticket/6677. Actucally it is a
regression of commit 99e07a4453732058df90885f80b3db3b4f37cb3c which
always inserts a dummy frame when decode the first key field picture.

Signed-off-by: Zhong Li <zhong.li at intel.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fd7cb86468cc63b5bda203d74964584281318cda
---

 libavcodec/mpegvideo.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 82b94253ae..c4089972f0 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -1283,8 +1283,7 @@ int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)
             s->pict_type, s->droppable);
 
     if ((!s->last_picture_ptr || !s->last_picture_ptr->f->buf[0]) &&
-        (s->pict_type != AV_PICTURE_TYPE_I ||
-         s->picture_structure != PICT_FRAME)) {
+        (s->pict_type != AV_PICTURE_TYPE_I)) {
         int h_chroma_shift, v_chroma_shift;
         av_pix_fmt_get_chroma_sub_sample(s->avctx->pix_fmt,
                                          &h_chroma_shift, &v_chroma_shift);
@@ -1294,9 +1293,6 @@ int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)
         else if (s->pict_type != AV_PICTURE_TYPE_I)
             av_log(avctx, AV_LOG_ERROR,
                    "warning: first frame is no keyframe\n");
-        else if (s->picture_structure != PICT_FRAME)
-            av_log(avctx, AV_LOG_DEBUG,
-                   "allocate dummy last picture for field based first keyframe\n");
 
         /* Allocate a dummy frame */
         i = ff_find_unused_picture(s->avctx, s->picture, 0);