[Ffmpeg-devel] An MPEG2/AC3 audio that ffmpeg cannot properly identify (or play)

Ronen Mizrahi ronen
Thu Sep 22 16:56:58 CEST 2005

It was grabbed by one of our users, this is what he had to say when I 
asked him the questions you asked me:
"The files are MPEG-TS (recorded from DVICO Fusion HDTV card using 
Fusion software to record in ts format - because the Fusion software 
option of recording in "native" mpeg mode doesn't work too well) run 
through Project-X with pretty much stock standard options set."

He later also added:
"Found the answer in Project-X, on the front screen! Tick the 
"MPG=>sPES" option."

So I guess some setting in Project-X needed to be changed for this to 
work well in all players, the quesiton however is if the original file 
was valid or not, and if it was valid why wasn't it properly identified 
by ffmpeg. If it was not valid then my apologies for taking your time 
for this.

M?ns Rullg?rd wrote:

>Bill May <wmay at cisco.com> writes:
>>Ronen Mizrahi wrote:
>>>I have an MPEG2 file recorded from an Australian DVB-T
>>>broadcast. When running ffmpeg -i on it this is what I get:
>>>ffmpeg version 0.4.9-pre1, build 4723, Copyright (c) 2000-2004
>>>Fabrice Bellard
>>> built on Sep  7 2005 17:43:26, gcc: 3.2.3 (mingw special 20030504-1)
>>>Input #0, mpeg, from 'd:\testmedia\Avril Lavigne test 2.MPG':
>>> Duration: 577014:01:50.9, bitrate: N/A
>>> Stream #0.0: Video: mpeg2video, 720x576, 25.00 fps
>>>Must supply at least one output file
>>>As you can see the audio stream is not identified, I know this is
>>>not the latest build, but if I am not mistaken not much has changed
>>>with regard ot mpeg2 and I tested also MPlayer and latest release of
>>>VLC and both of them fail to play the audio. Mplayer Classic on the
>>>other hand (as well as Windows Media Player or any other directshow
>>>based player) can play the audio just fine.
>>>If you would like you can download a sample from:
>>The substream value is 0xb, instead of 0x80 to 0x90 which would
>>be required for AC3.  (substream is the value after the PES header),
>>values 0x80 to 0x90 indicate AC3, 0xa0 to 0xb0 indicate LPCM.
>That's only for DVD.  In general, private stream 1 can contain
>anything.  In this case it contains raw ac3 audio, no substreams or
>such things.
>What is the exact origin of this file?  DVB typically uses MPEG-TS,
>but this is MPEG-PS.  Has it been remuxed?  What software did you use
>to grab it?

More information about the ffmpeg-devel mailing list