fftools/ffmpeg: add an option for writing pre-muxing stats

Analogous to -enc_stats*, but happens right before muxing. Useful
because bitstream filters and the sync queue can modify packets after
encoding and before muxing. Also has access to the muxing timebase.

1 files changed, 9 insertions, 4 deletions

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index 592c4b4393..076956d128 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -2063,14 +2063,17 @@ or invalid output files.
 
 @item -enc_stats_pre[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
 @item -enc_stats_post[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
+@item -stats_mux_pre[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
 Write per-frame encoding information about the matching streams into the file
 given by @var{path}.
 
 @option{-enc_stats_pre} writes information about raw video or audio frames right
 before they are sent for encoding, while @option{-enc_stats_post} writes
-information about encoded packets as they are received from the encoder. Every
-frame or packet produces one line in the specified file. The format of this line
-is controlled by @option{-enc_stats_pre_fmt} / @option{-enc_stats_post_fmt}.
+information about encoded packets as they are received from the encoder.
+@option{-stats_mux_pre} writes information about packets just as they are about to
+be sent to the muxer. Every frame or packet produces one line in the specified
+file. The format of this line is controlled by @option{-enc_stats_pre_fmt} /
+@option{-enc_stats_post_fmt} / @option{-stats_mux_pre_fmt}.
 
 When stats for multiple streams are written into a single file, the lines
 corresponding to different streams will be interleaved. The precise order of
@@ -2079,8 +2082,9 @@ different invocations of the program, even with the same options.
 
 @item -enc_stats_pre_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
 @item -enc_stats_post_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
+@item -stats_mux_pre_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
 Specify the format for the lines written with @option{-enc_stats_pre} /
-@option{-enc_stats_post}.
+@option{-enc_stats_post} / @option{-stats_mux_pre}.
 
 @var{format_spec} is a string that may contain directives of the form
 @var{@{fmt@}}. @var{format_spec} is backslash-escaped --- use \@{, \@}, and \\
@@ -2097,6 +2101,7 @@ Index of the output stream in the file.
 @item n
 Frame number. Pre-encoding: number of frames sent to the encoder so far.
 Post-encoding: number of packets received from the encoder so far.
+Muxing: number of packets submitted to the muxer for this stream so far.
 
 @item ni
 Input frame number. Index of the input frame (i.e. output by a decoder) that