Copied from www.go-opensource.org: Go Open Source campaign projects are aimed at creating awareness, educating and providing access to open source software. Sponsors of the campaign are among others spacetraveller Shuttleworth foundation and his company Canonical (of Ubuntu linux fame).
Their TV show go_open is available (Creative Commons licensed) for download via BitTorrent. The files are in .MP4-format with Mpeg4-video and audio (AAC). I wanted to check them out, so I downloaded the torrent but ran into problems when trying to play them. While media playback of popular formats such as MP3-audio and AVI/MOV-embedded video & audio is a problem in itself for most linux distributions (due to patent issues), most files can be played anyways (with some legal issues depending on which country you live in) using mediaplayers such as VLC, Xine and MPlayer. Mpeg4-class video is very well working in all players but I found AAC (Mpeg4-class audio) to be buggy on my box, seemingly because of some API-inconsistency in the faad2-decoder (VLC messages says faad warning: Unexpected channel configuration change). This is on a Fedora Core 4 box using packages from the livna.org repository. A search on google confirmed that many other users on various distributions had the same problems playing the go_open videos.
After toying around a while I found out that:
(1) faad is a standalone tool that without any problems extracted the AAC-stream into a play-anywhere WAV-stream.
(2) ffmpeg is a powerful encoder that easily multiplexes this WAV-stream converted into MP3-audio with the Mpeg4-video, throwing away the old AAC-stream.
Thinking that someone else may run into the same problem, here's the bash-script i hacked together, converting all .MP4-files in the current directory. All 13 episodes should take ~45 minutes to convert on a modern machine.
As of writing this I haven't had time to look at the show, so this post is distributed to you WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ;-)
I have run into the same problem and have tried the script you attached (nice idea btw!), however I cannot get it to to run properly. I get this error on the ffmpeg command:
ReplyDeleteffmpeg version 0.4.9-pre1, build 4718, Copyright (c) 2000-2004 Fabrice Bellard
built on Nov 28 2004 13:29:10, gcc: 3.3.3 (SuSE Linux)
Input #0, mov,mp4,m4a,3gp, from 'go-open-episode-01.mp4':
Duration: N/A, bitrate: N/A
Input #1, wav, from 'go-open-episode-01.wav':
Duration: 00:23:55.9, bitrate: 705 kb/s
Stream #1.0: Audio: pcm_s16le, 22050 Hz, stereo, 705 kb/s
Number of stream maps must match number of output streams
Seems to be something with the map parameters? I've played around with them a bit but all I can get now is the audio track but no video (the opposite of the original problem!)
I had the same problem with some MPEG4 files I downloaded from archive.org. The shell script helped (I was able to play the things at least), but the audio/video sync was all over the place. Then again, that could just be because firefox is trying to take all my CPU time right now :-(
ReplyDelete