[FFmpeg-devel] [PATCH] lavf: consider codec timebase for framerate detection

[wm4]

Fixes detection of some TV sample as 24.5 FPS. With the patch applied,
it's detected as 25 FPS.
---
 libavformat/utils.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/libavformat/utils.c b/libavformat/utils.c
index fbd8b58ac2..778a82aeee 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -3903,6 +3903,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
                 st->info->codec_info_duration) {
                 int best_fps      = 0;
                 double best_error = 0.01;
+                AVRational codec_frame_rate = av_inv_q(avctx->time_base);
 
                 if (st->info->codec_info_duration        >= INT64_MAX / st->time_base.num / 2||
                     st->info->codec_info_duration_fields >= INT64_MAX / st->time_base.den ||
@@ -3924,6 +3925,27 @@ FF_ENABLE_DEPRECATION_WARNINGS
                         best_fps   = std_fps.num;
                     }
                 }
+                if (avctx->ticks_per_frame > 0)
+                    codec_frame_rate.num /= avctx->ticks_per_frame;
+                for (j = 0; j < MAX_STD_TIMEBASES; j++) {
+                    AVRational std_fps = { get_std_framerate(j), 12 * 1001 };
+                    double error       = fabs(av_q2d(st->avg_frame_rate) /
+                                              av_q2d(std_fps) - 1);
+
+                    if (error < best_error) {
+                        best_error = error;
+                        best_fps   = std_fps.num;
+                    }
+
+                    if (codec_frame_rate.num > 0 && codec_frame_rate.den > 0) {
+                        error       = fabs(av_q2d(codec_frame_rate) /
+                                           av_q2d(std_fps) - 1);
+                        if (error < best_error) {
+                            best_error = error;
+                            best_fps   = std_fps.num;
+                        }
+                    }
+                }
                 if (best_fps)
                     av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
                               best_fps, 12 * 1001, INT_MAX);
-- 
2.11.0