[FFmpeg-devel] [PATCH] fftools/ffplay: fix rotation incorrect when frame contains the side_data(type is AV_FRAME_DATA_DISPLAYMATRIX)

[Steven Liu]

Steven Liu <lingjiujianke at gmail.com> 于2022年9月1日周四 09:17写道：
>
> Zhao Zhili <quinkblack at foxmail.com> 于2022年9月1日周四 00:34写道：
> >
> >
> >
> > > -----Original Message-----
> > > From: ffmpeg-devel-bounces at ffmpeg.org <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of 1035567130 at qq.com
> > > Sent: 2022年8月31日 18:45
> > > To: ffmpeg-devel at ffmpeg.org
> > > Cc: Wang Yaqiang <wangyaqiang03 at kuaishou.com>; 1445440736 at qq.com
> > > Subject: [FFmpeg-devel] [PATCH] fftools/ffplay: fix rotation incorrect when frame contains the side_data(type is
> > > AV_FRAME_DATA_DISPLAYMATRIX)
> > >
> > > From: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
> > >
> > > For example, if the jpeg contains exif information and the rotation direction is included in the exif,
> > > the displaymatrix will be set on the side_data of the frame when decoding.
> > > However, when ffplay is used to play the image, only the side data in the stream will be determined.
> > > It does not check whether the frame also contains rotation information, causing it to play in the wrong direction
> >
> > When both per-stream and per-frame DISPLAYMATRIX exist, we need to decode how they work
> > together. Does one applied after the other, or one override the other? I have no idea.
> I think we should "Does one applied after the other", do frame rotate
> adter stream rotate, because user maybe not need every frames rotate.
BTW,  we get jpeg picture need rotate by exif, but there have no
rotate data in stream,
the other sample we get there have rotate in stream only.
have not get rotate data in one time both stream and frames by one sample yet,
So we think it should do twice rotate operation in ffplay. because it
have no problem in ffmpeg, so we only modify ffplay.
>
> >
> > Secondly, even If one is applied after the other, we shouldn't use two rotation filter
> > but merge the operation into a single one.
> Agreed, should merge two rotate value into. one value.
> >
> > > ---
> > >  fftools/ffplay.c | 12 +++++++++++-
> > >  1 file changed, 11 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fftools/ffplay.c b/fftools/ffplay.c
> > > index 9242047f5c..868123dc65 100644
> > > --- a/fftools/ffplay.c
> > > +++ b/fftools/ffplay.c
> > > @@ -1917,7 +1917,8 @@ static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const c
> > >      if (autorotate) {
> > >          int32_t *displaymatrix = (int32_t *)av_stream_get_side_data(is->video_st, AV_PKT_DATA_DISPLAYMATRIX, NULL);
> > >          double theta = get_rotation(displaymatrix);
> > > -
> > > +        int frame_rotation_checked = 0;
> > > +    rotation:
> > >          if (fabs(theta - 90) < 1.0) {
> > >              INSERT_FILT("transpose", "clock");
> > >          } else if (fabs(theta - 180) < 1.0) {
> > > @@ -1930,6 +1931,15 @@ static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const c
> > >              snprintf(rotate_buf, sizeof(rotate_buf), "%f*PI/180", theta);
> > >              INSERT_FILT("rotate", rotate_buf);
> > >          }
> > > +        if (!frame_rotation_checked) {
> > > +            frame_rotation_checked = 1;
> > > +            AVFrameSideData *sd = av_frame_get_side_data(frame,AV_FRAME_DATA_DISPLAYMATRIX);
> > > +            if (sd) {
> > > +                displaymatrix = (int32_t *)sd->data;
> > > +                theta = get_rotation(displaymatrix);
> > > +                goto rotation;
> > > +            }
> > > +        }
> > >      }
> > >
> > >      if ((ret = configure_filtergraph(graph, vfilters, filt_src, last_filter)) < 0)
> > > --
> > > 2.33.0
> > >
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