demux_lavf: disable support for byte-based seeking

libavformat returns nonsense per-stream bitrate values for some MPEG
files (0 or many times higher than the overall bitrate of the file),
which triggered the heuristic to enable byte-based seeking in
demux_lavf and then made the byte-based seeks wildly inaccurate.
Disable the support for byte-based seeks. This will avoid problems
with files that have consistent timestamps, but on the other hand will
completely break seeking in MPEG files that have timestamp resets.
I'll probably add at least an option to manually enable byte-based
seeking later.

1 files changed, 4 insertions, 0 deletions

diff --git a/libmpdemux/demux_lavf.c b/libmpdemux/demux_lavf.c
index ed8a3ddb69..3aca4b603c 100644
--- a/libmpdemux/demux_lavf.c
+++ b/libmpdemux/demux_lavf.c
@@ -615,6 +615,9 @@ static demuxer_t* demux_open_lavf(demuxer_t *demuxer){
         demuxer->video->id=-2; // audio-only
     } //else if (best_video > 0 && demuxer->video->id == -1) demuxer->video->id = best_video;
 
+    // disabled because unreliable per-stream bitrate values returned
+    // by libavformat trigger this heuristic incorrectly and break things
+#if 0
     /* libavformat sets bitrate for mpeg based on pts at start and end
      * of file, which fails for files with pts resets. So calculate our
      * own bitrate estimate. */
@@ -630,6 +633,7 @@ static demuxer_t* demux_open_lavf(demuxer_t *demuxer){
         if (!priv->bitrate)
             priv->bitrate = 1440000;
     }
+#endif
     demuxer->accurate_seek = !priv->seek_by_bytes;
 
     return demuxer;