[FFmpeg-devel] [PATCH] fftools/ffplay.c: fix rotate error when displaymatrix contains flip

[Marton Balint]

On Thu, 9 Mar 2023, 1035567130 at qq.com wrote:

> From: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
>
> The angle is calculated by the get_rotation function,
> but it needs to be combined with the displaymatrix to determine whether flip or rotate,
> which is consistent with the processing logic in ffmpeg_filter.c

If there is common logic, then it should be factorized to a shared 
function and both ffmpeg and ffplay should use that.

Regards,
Marton

>
> Signed-off-by: Wang Yaqiang <wangyaqiang03 at kuaishou.com>
> ---
> fftools/ffplay.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/fftools/ffplay.c b/fftools/ffplay.c
> index d6479aef5f..860bac367a 100644
> --- a/fftools/ffplay.c
> +++ b/fftools/ffplay.c
> @@ -1925,16 +1925,24 @@ static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const c
>         theta = get_rotation(displaymatrix);
>
>         if (fabs(theta - 90) < 1.0) {
> -            INSERT_FILT("transpose", "clock");
> +            INSERT_FILT("transpose", displaymatrix[3] > 0 ? "cclock_flip" : "clock");
>         } else if (fabs(theta - 180) < 1.0) {
> -            INSERT_FILT("hflip", NULL);
> -            INSERT_FILT("vflip", NULL);
> +            if (displaymatrix[0] < 0) {
> +                INSERT_FILT("hflip", NULL);
> +            }
> +            if (displaymatrix[4] < 0) {
> +                INSERT_FILT("vflip", NULL);
> +            }
>         } else if (fabs(theta - 270) < 1.0) {
> -            INSERT_FILT("transpose", "cclock");
> +            INSERT_FILT("transpose", displaymatrix[3] < 0 ? "clock_flip" : "cclock");
>         } else if (fabs(theta) > 1.0) {
>             char rotate_buf[64];
>             snprintf(rotate_buf, sizeof(rotate_buf), "%f*PI/180", theta);
>             INSERT_FILT("rotate", rotate_buf);
> +        } else if (fabs(theta) < 1.0) {
> +            if (displaymatrix && displaymatrix[4] < 0) {
> +                INSERT_FILT("vflip", NULL);
> +            }
>         }
>     }
>
> -- 
> 2.39.2
>
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