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

[Steven Liu]

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.

>
> 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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