From cc2a2fc37cfa25ec1b8a4c2a93d0f34bd4c7d1f3 Mon Sep 17 00:00:00 2001
From: Martin Pulec <martin.pulec@cesnet.cz>
Date: Tue, 17 Feb 2026 16:05:27 +0100
Subject: [PATCH] vcomp/lavc: improve time_base setting

for /1001 formats eg. 29.97, 1/30 was set - improve to set 1001/30000

for AVCodecCtx.framerate just invert the time_base fraction
---
 src/video_compress/libavcodec.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/video_compress/libavcodec.cpp b/src/video_compress/libavcodec.cpp
index 40996dd5a..2d1cb1e02 100644
--- a/src/video_compress/libavcodec.cpp
+++ b/src/video_compress/libavcodec.cpp
@@ -43,6 +43,7 @@
 #include <cmath>
 #include <cstdint>
 #include <cstring>                        // for strcmp, strlen, strstr, strchr
+#include <libavutil/rational.h>           // for av_inv_q
 #include <list>
 #include <map>
 #include <regex>
@@ -953,9 +954,9 @@ bool set_codec_ctx_params(struct state_video_compress_libav *s, AVPixelFormat pi
         s->codec_ctx->width = desc.width;
         s->codec_ctx->height = desc.height;
         /* frames per second */
-        s->codec_ctx->time_base = (AVRational){1,(int) desc.fps};
-        s->codec_ctx->framerate    = (AVRational) { get_framerate_n(desc.fps),
-                                                    get_framerate_d(desc.fps) };
+        s->codec_ctx->time_base = (AVRational) { get_framerate_d(desc.fps),
+                                                 get_framerate_n(desc.fps) };
+        s->codec_ctx->framerate = av_inv_q(s->codec_ctx->time_base);
         s->codec_ctx->gop_size = s->requested_gop;
         s->codec_ctx->max_b_frames = 0;