vd_lavc: add an option to explicitly workaround x264 4:4:4 bug

Technically, the user could just use --vd-lavc-o with the same result.
But I find it better to make this an explicit option, so we can document
the ups and downs, and also avoid setting it for non-h264.

1 files changed, 12 insertions, 0 deletions

diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index e76f5a115a..baf8f3a6d5 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -1159,6 +1159,18 @@ Video
     on the machine and use that, up to the maximum of 16. You can set more than
     16 threads manually.
 
+``--vd-lavc-assume-old-x264=<yes|no>``
+    Assume the video was encoded by an old, buggy x264 version (default: no).
+    Normally, this is autodetected by libavcodec. But if the bitstream contains
+    no x264 version info (or it was somehow skipped), and the stream was in fact
+    encoded by an old x264 version (build 150 or earlier), and if the stream
+    uses ``4:4:4`` chroma, then libavcodec will by default show corrupted video.
+    This option sets the libavcodec ``x264_build`` option to ``150``, which
+    means that if the stream contains no version info, or was not encoded by
+    x264 at all, it assumes it was encoded by the old version. Enabling this
+    option is pretty safe if you want your broken files to work, but in theory
+    this can break on streams not encoded by x264, or if a stream encoded by a
+    newer x264 version contains no version info.
 
 
 Audio