doc/muxers: add documentation for the md5 and framemd5 muxers

Address trac ticket #1153.

doc/muxers.texi

@@ -96,6 +96,39 @@ ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
 
 See also the @ref{crc} muxer.
 
+@anchor{framemd5}
+@section framemd5
+
+Per-packet MD5 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.
+
+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}
+@end example
+
+@var{MD5} is a hexadecimal number representing the computed MD5 hash
+for the packet.
+
+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}:
+@example
+ffmpeg -i INPUT -f framemd5 out.md5
+@end example
+
+To print the information to stdout, use the command:
+@example
+ffmpeg -i INPUT -f framemd5 -
+@end example
+
+See also the @ref{md5} muxer.
+
 @anchor{image2}
 @section image2
 
@@ -154,6 +187,33 @@ each of the YUV420P components. To read or write this image file format,
 specify the name of the '.Y' file. The muxer will automatically open the
 '.U' and '.V' files as required.
 
+@anchor{md5}
+@section md5
+
+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.
+
+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.
+
+For example 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
+@end example
+
+You can print the MD5 to stdout with the command:
+@example
+ffmpeg -i INPUT -f md5 -
+@end example
+
+See also the @ref{framemd5} muxer.
+
 @section MOV/MP4/ISMV
 
 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4