From 60e4e430dbf64791d430f1527bec36c196355eb7 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Sat, 7 Apr 2012 10:44:07 +0200 Subject: doc/muxers: clarify documentation for the framecrc muxer Makes more explicit that framecrc works at the packet level, also prefers the term "packet" over "frame" when it makes sense. --- doc/muxers.texi | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) (limited to 'doc/muxers.texi') diff --git a/doc/muxers.texi b/doc/muxers.texi index 7fd6548ea4..c257ab2b24 100644 --- a/doc/muxers.texi +++ b/doc/muxers.texi @@ -56,31 +56,37 @@ See also the @ref{framecrc} muxer. @anchor{framecrc} @section framecrc -Per-frame CRC (Cyclic Redundancy Check) testing format. +Per-packet CRC (Cyclic Redundancy Check) testing format. -This muxer computes and prints the Adler-32 CRC for each decoded audio -and video frame. By default audio frames are converted to signed +This muxer computes and prints the Adler-32 CRC for each audio +and video packet. By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before computing the CRC. The output of the muxer consists of a line for each audio and video -frame of the form: @var{stream_index}, @var{frame_dts}, @var{frame_pts}, @var{frame_duration}, -@var{frame_size}, 0x@var{CRC}, where @var{CRC} is a hexadecimal -number 0-padded to 8 digits containing the CRC of the decoded frame. +packet of the form: +@example +@var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, 0x@var{CRC} +@end example -For example to compute the CRC of each decoded frame in the input, and -store it in the file @file{out.crc}: +@var{CRC} is a hexadecimal number 0-padded to 8 digits containing the +CRC of the packet. + +For example to compute the CRC of the audio and video frames in +@file{INPUT}, converted to raw audio and video packets, and store it +in the file @file{out.crc}: @example ffmpeg -i INPUT -f framecrc out.crc @end example -You can print the CRC of each decoded frame to stdout with the command: +To print the information to stdout, use the command: @example ffmpeg -i INPUT -f framecrc - @end example -You can select the output format of each frame with @command{ffmpeg} by -specifying the audio and video codec and format. For example, to +With @command{ffmpeg}, you can select the output format to which the +audio and video frames are encoded before computing the CRC for each +packet by specifying the audio and video codec. For example, to compute the CRC of each decoded input audio frame converted to PCM unsigned 8-bit and of each decoded input video frame converted to MPEG-2 video, use the command: -- cgit v1.2.3