From f4a0236cbd75249418b40e8aa88b0264c0b58b69 Mon Sep 17 00:00:00 2001 From: Moritz Barsnick Date: Tue, 12 Apr 2016 11:16:18 -0300 Subject: avformat: add hash and framehash muxers Reviewed-by: Michael Niedermayer Signed-off-by: Moritz Barsnick Signed-off-by: James Almer --- doc/muxers.texi | 125 ++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 103 insertions(+), 22 deletions(-) (limited to 'doc') diff --git a/doc/muxers.texi b/doc/muxers.texi index 2aafbad194..042efcea9e 100644 --- a/doc/muxers.texi +++ b/doc/muxers.texi @@ -174,30 +174,70 @@ ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc - See also the @ref{crc} muxer. -@anchor{framemd5} -@section framemd5 +@anchor{framehash} +@section framehash -Per-packet MD5 testing format. +Per-packet hash testing format. -This muxer computes and prints the MD5 hash 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 -hash. +This muxer computes and prints a cryptographic hash for each audio +and video packet. This can be used for packet-by-packet equality +checks without having to individually do a binary comparison on each. + +By default audio frames are converted to signed 16-bit raw audio and +video frames to raw video before computing the hash, but the output +of explicit conversions to other codecs can also be used. It uses the +SHA-256 cryptographic hash function by default, but supports several +other algorithms. The output of the muxer consists of a line for each audio and video packet of the form: @example -@var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{MD5} +@var{stream_index}, @var{packet_dts}, @var{packet_pts}, @var{packet_duration}, @var{packet_size}, @var{hash} @end example -@var{MD5} is a hexadecimal number representing the computed MD5 hash +@var{hash} is a hexadecimal number representing the computed hash for the packet. +@table @option +@item hash @var{algorithm} +Use the cryptographic hash function specified by the string @var{algorithm}. +Supported values include @code{MD5}, @code{murmur3}, @code{RIPEMD128}, +@code{RIPEMD160}, @code{RIPEMD256}, @code{RIPEMD320}, @code{SHA160}, +@code{SHA224}, @code{SHA256} (default), @code{SHA512/224}, @code{SHA512/256}, +@code{SHA384}, @code{SHA512}, @code{CRC32} and @code{adler32}. + +@end table + @subsection Examples -For example to compute the MD5 of the audio and video frames in -@file{INPUT}, converted to raw audio and video packets, and store it -in the file @file{out.md5}: +To compute the SHA-256 hash of the audio and video frames in @file{INPUT}, +converted to raw audio and video packets, and store it in the file +@file{out.sha256}: +@example +ffmpeg -i INPUT -f framehash out.sha256 +@end example + +To print the information to stdout, using the MD5 hash function, use +the command: +@example +ffmpeg -i INPUT -f framehash -hash md5 - +@end example + +See also the @ref{hash} muxer. + +@anchor{framemd5} +@section framemd5 + +Per-packet MD5 testing format. + +This is a variant of the @ref{framehash} muxer. Unlike that muxer, +it defaults to using the MD5 hash function. + +@subsection Examples + +To compute the MD5 hash of the audio and video frames in @file{INPUT}, +converted to raw audio and video packets, and store it in the file +@file{out.md5}: @example ffmpeg -i INPUT -f framemd5 out.md5 @end example @@ -207,7 +247,7 @@ To print the information to stdout, use the command: ffmpeg -i INPUT -f framemd5 - @end example -See also the @ref{md5} muxer. +See also the @ref{framehash} and @ref{md5} muxers. @anchor{gif} @section gif @@ -243,6 +283,51 @@ ffmpeg -i INPUT -c:v gif -f image2 "out%d.gif" Note 2: the GIF format has a very small time base: the delay between two frames can not be smaller than one centi second. +@anchor{hash} +@section hash + +Hash testing format. + +This muxer computes and prints a cryptographic hash of all the input +audio and video frames. This can be used for equality checks without +having to do a complete binary comparison. + +By default audio frames are converted to signed 16-bit raw audio and +video frames to raw video before computing the hash, but the output +of explicit conversions to other codecs can also be used. Timestamps +are ignored. It uses the SHA-256 cryptographic hash function by default, +but supports several other algorithms. + +The output of the muxer consists of a single line of the form: +@var{algo}=@var{hash}, where @var{algo} is a short string representing +the hash function used, and @var{hash} is a hexadecimal number +representing the computed hash. + +@table @option +@item hash @var{algorithm} +Use the cryptographic hash function specified by the string @var{algorithm}. +Supported values include @code{MD5}, @code{murmur3}, @code{RIPEMD128}, +@code{RIPEMD160}, @code{RIPEMD256}, @code{RIPEMD320}, @code{SHA160}, +@code{SHA224}, @code{SHA256} (default), @code{SHA512/224}, @code{SHA512/256}, +@code{SHA384}, @code{SHA512}, @code{CRC32} and @code{adler32}. + +@end table + +@subsection Examples + +To compute the SHA-256 hash of the input converted to raw audio and +video, and store it in the file @file{out.sha256}: +@example +ffmpeg -i INPUT -f hash out.sha256 +@end example + +To print an MD5 hash to stdout use the command: +@example +ffmpeg -i INPUT -f hash -hash md5 - +@end example + +See also the @ref{framehash} muxer. + @anchor{hls} @section hls @@ -629,16 +714,12 @@ have no effect if it is not. MD5 testing format. -This muxer computes and prints the MD5 hash of all the input audio -and video frames. By default audio frames are converted to signed -16-bit raw audio and video frames to raw video before computing the -hash. Timestamps are ignored. +This is a variant of the @ref{hash} muxer. Unlike that muxer, it +defaults to using the MD5 hash function. -The output of the muxer consists of a single line of the form: -MD5=@var{MD5}, where @var{MD5} is a hexadecimal number representing -the computed MD5 hash. +@subsection Examples -For example to compute the MD5 hash of the input converted to raw +To compute the MD5 hash of the input converted to raw audio and video, and store it in the file @file{out.md5}: @example ffmpeg -i INPUT -f md5 out.md5 @@ -649,7 +730,7 @@ You can print the MD5 to stdout with the command: ffmpeg -i INPUT -f md5 - @end example -See also the @ref{framemd5} muxer. +See also the @ref{hash} and @ref{framemd5} muxers. @section mov, mp4, ismv -- cgit v1.2.3