On Thu, May 16, 2019 at 7:38 PM Vittorio Giovara <vittorio.giov...@gmail.com> wrote:
> On Thu, May 16, 2019 at 9:32 PM Jun Li <junli1...@gmail.com> wrote: > > > On Thu, May 16, 2019 at 4:34 PM Ted Meyer < > > tmathmeyer-at-google....@ffmpeg.org> wrote: > > > > > Right now ffmpeg doesn't export a mirroring status when checking the > > > display matrix for rotation. > > > Here is an example video: https://files.tedm.io/flip.mp4 > > > -Ted > > > _______________________________________________ > > > ffmpeg-devel mailing list > > > ffmpeg-devel@ffmpeg.org > > > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > > > To unsubscribe, visit link above, or email > > > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > > > > > > There is a patch but not merged into master, quality not guaranteed :) > > Hope this helps. > > https://patchwork.ffmpeg.org/patch/13130/ > > > > hey i just noticed this patch > > + if (CONV_FP(m[0]) * CONV_FP(m[4]) < CONV_FP(m[1]) * > CONV_FP(m[3])) {+ *hflip = 1;+ av_display_matrix_flip(m, > 1, 0);+ } > > the long if is basically computing the determinant of the matrix, but you > only need the fact whether it's positive or negative, you can discard the > result so you can avoid converting to CONV_FP, and just cast to int64_t > + return av_display_rotation_get(m); > > don't you need to set vertical flip only if det < 0 and rot = 180? > I think it should be fine and not need to check. Because vlip could be represented as hflip+rotation, the cross product (Michael's brilliant idea) m[0] * m[4] - m[1]*[3] cannot reflect it is horizontal or vertical flip. It all depends how we want to represents the transform, it could be "rotation+hflip" or "rotation+vlip". Any combination of rotation+flip can be represented by either one. > beside that small point, this patch introduces an api that basically > supersedes the normal av_display_rotation_get(), and does many more things, > I'd be tempted to deprecate any other use, and what do you think? in that > case you could just call it av_display_rotation_get2() like is tradition I can't find the other patches from the set to review, would you be able to > send an updated version? > Thanks Vittorio, I updated the version as suggested: https://patchwork.ffmpeg.org/patch/13181/ The original patch includes two part, but I am going to abandon it after discussing with Nicolas. The patches were for per frame flip/mirror and rotation. Basically it checks every frame's meta-data and address flip or rotation or both. I think it also covers stream level flip, addressed in ffmpeg_filter.c (correct me if I am wrong). https://patchwork.ffmpeg.org/patch/13131/ https://patchwork.ffmpeg.org/patch/13130/ Best Regards, Jun > thanks > -- > Vittorio > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
