On 2021-07-30 00:00, Andreas Rheinhardt wrote:
Gyan Doshi:--- doc/bitstream_filters.texi | 64 ++++++++++++--- libavcodec/noise_bsf.c | 161 +++++++++++++++++++++++++++++++++---- tests/fate/matroska.mak | 2 +- 3 files changed, 199 insertions(+), 28 deletions(-) diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi index d10842ae47..46e4869f80 100644 --- a/doc/bitstream_filters.texi +++ b/doc/bitstream_filters.texi @@ -534,20 +534,62 @@ container. Can be used for fuzzing or testing error resilience/concealment. Parameters: @table @option @item amount -A numeral string, whose value is related to how often output bytes will -be modified. Therefore, values below or equal to 0 are forbidden, and -the lower the more frequent bytes will be modified, with 1 meaning -every byte is modified. -@item dropamount -A numeral string, whose value is related to how often packets will be dropped. -Therefore, values below or equal to 0 are forbidden, and the lower the more -frequent packets will be dropped, with 1 meaning every packet is dropped. +Accepts an expression whose evaluation per-packet determines how often bytes in that +packet will be modified. A value below 0 will result in a variable frequency. +Default is 0 which results in no modification. However, if neither amount or drop is specified, +amount will be set to @var{-1}. See below for accepted variables. +@item drop, dropamount +Accepts an expression evaluated per-packet whose value determines whether that packet is dropped. +Evaluation to a positive value results in the packet being dropped. Evaluation to a negative +value results in a variable chance of it being dropped, roughly inverse in proportion to the magnitude +of the value. Default is 0 which results in no drops. See below for accepted variables.Negating the dropamount scale broke all prior usages of it.
Yes, with eval used now, the semantics for positive values was best changed, so I mapped the old usage to negative values.
I've rarely seen this filter used in the wild. The only FATE test that employs it uses it incidentally.
I'll add a note to the docs noting the legacy use and its remapping. Regards, Gyan _______________________________________________ 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".
