Hanno's blog

I've promised that I'll dig into some old file formats and check how well they can be accessed on today's systems with free software.

Today, I'll start with audio formats. To begin, in general there are two kinds of audio formats. Streamed audio formats start with a more or less raw audio stream, apply some encoding and sometimes (lossless or lossy) compression. There are also tracker audio formats. They have internal information on tone pitches and instruments. Most really old computer audio files are tracker formats (like the popular C64 SID format). This blog post will be about streamed audio formats and I'll save the tracked ones for a later one.

The file formats I've chosen are more or less random, the main criteria being that I once stepped over them and still remember that. There's a hughe collection of all kinds of media file samples on the mplayer server.

The single most important project regarding exotic audio or video formats is ffmpeg, a library that does despite its name much more than decoding mpeg. All major free software media players use ffmpeg.

The file formats I've investigated:

• Some of the very first files distributing music through the Internet I remember were real audio files (extension .ra or .rm) from the german punk band WIZO. Real audio has a whole bunch of variants, scanning through some of my old backups, most of them used either AC-3 or Real Audio 2.0 as their codec. Thanks to Waybach Machine, you can still find the WIZO downloads (Raum der Zeit - Techno is AC-3, the others are RealAudio 2.0).
• vqf (or TwinVQ) was once announced having better quality than MP3 and was discussed as its successor. However, it seems it is almost completely distinct today, I didn't find anything at all (except in the above mentioned sample collection) in vqf format for download.
• Monkey's audio, extension .ape, is a lossless audio codec, which is itself licensed under some kind of noncommercial-use-only license that doesn't qualify as free software. It's not really old, as it's still being developed, but I added it as another example of an uncommon format.
• Shorten (extension shn) is an old lossless audio format, which was often used by the etree project that collects recordings of concerts. Today, it is mostly deprecated by flac, but the old recordings are still available.
• voc: The popular dos floppy copying program vgacopy had sound before I had a soundcard - it used the pc speaker to play .voc files it had shipped. It's a format used by some Creative software for their SoundBlaster. It's a more-or-less raw audio format like wav.

ffmpeg is able to decode and play all of these audio codecs. But what I found out was that this doesn't necessarily mean every application using ffmpeg can do this as well. I've tested mplayer, xine, vlc, audacious and totem (based on gstreamer). Although there are quite many free software media players - both for audio and video - out there, this should cover pretty much everything. Most media players use xine, vlc or gstreamer indirectly.

	mplayer	xine	vlc	audacious	totem/gstreamer
ra AC3	Yes	No Yes	Yes	Yes	No
ra 2.0	Yes	No	No	Yes	No
vqf	Yes	No	Yes	Yes	No
ape	Yes	No	No	Yes	Yes
shn	Yes	Yes	No	Yes	Yes
voc	Yes	Scratchy	Scratchy	No	No

Shorten playback has some problems, seeking often does not work, but this seems to be a limitation of the format itself. If I found feature requests for those formats, I've linked them, I also opened a bunch of them myself.

Conclusion: ffmpeg does a really fine job in playing all the obscure audio streaming formats. However, not every player that's based on ffmpeg plays every format ffmpeg can play. mplayer is the only player that succeeds with everything, probably because mplayer's devleopment is very tightly related to ffmpeg's development.

Update: I forgot to mention libav. It is a fork of ffmpeg. However, there's not that much to say, as ffmpeg and libav are still quite similar in their codec support. audacious does not support libav yet, all other apps just produce the same result.

I recently had a discussion about the accessibility of today's computer content in the future. We started asking ourselves how well the support in current software is to read and use old legacy data formats - graphics, videos, text, layout documents, whatever may still be interesting today.

I remembered having such a discussion some years ago and back then, Works documents were mentioned by someone as a somewhat difficult format. Back then, libwps existed with some command line tools to convert to staroffice format (which could then be opened by openoffice) and experimental patches existed for openoffice itself. Seems at least here the situation has improved. The current version of libreoffice reads Works documents out of the box.

Free software projects play an important role in keeping old data accessible. Just to name two, ffmpeg does a great job in supporting a large number of old and exotic video formats. It's used by a bunch of popular video players like mplayer and vlc. For graphics files, there is imagemagick, which provides a conversion tool to up-to-date formats like PNG.

In some upcoming blog entries, I'll try to explore things, will look for old files and see if I am able to use them.

A call to my readers: Do you have any old stuff laying around that you'd find interesting to access today? Which file formats are difficult to access? Are you searching for tools to open / convert them? Do you have something old that might be worth publishing to others as well? Send me your stuff, I'm very interested.

The free software projects for media playing did a good job in the past on supporting a wide variety of formats. From the common to many very obscure formats, current versions of the free software mediaplayers were usually able to play them. Today it's even common to suggest vlc for Windows users if they can't play unusual media formats.

Though there were a few exceptions, the most notable probably the long-time missing support for many of the Real formats. While these are rarely used today, many archived videos in the Internet still rely on it. For example, many german television stations provide real video files on their webpages.

Recently and without much public notion, ffmpeg first got support for RV40, some weeks later also for RV30. This fills a long time gap in free software support for video formats. ffmpeg is used by all major free software video players (vlc, xine, mplayer), so you should get the support within some time in all of them. For now, it's quite easy to checkout mplayer from subversion and build it on your own.

Want something to try out? Here's a video from Desert Planet in real format.

The only gap I know of a format that really got usage in the wild and that is not yet supported by free software is WMA3.

This friday, there were two driver releases for linux graphics hardware. A new proprietary driver from nvidia and a new free driver for ati cards.

The release of the new nvidia driver was spread over all major news-pages. It's main new feature was the support of Xorg 7.1 just three months after it's release and about five months after the first release candidate. It still doesn't support the main new feature of Xorg 7.1, which is AIGLX. I couldn't find the release of the new free ati driver mentioned anywhere (even on linux news-pages) and probably even wouldn't have noticed if I wouldn't read the xorg-mailinglist. The new ati driver has much improved support for r300 and above chips, which is very important for the future development of 3D-desktops like compiz.

Now, the reason why this happens is probably that nvidia put out a colorful press release when they update their drivers. One could say that it's bad journalism from those news pages (especially if they are linux related) that if they get press releases from companies, they always post news, but they don't do so for rarely announced free releases. But news writers are lazy, if they get some ready-to-publish press release, they'll more likely take it than grabbing some announcement from some developers mailinglist. The problem from many free software projects is that their publicity sucks.

The work done by the xorg-developers to the ati-drivers is great. But I still meet people that even don't know the free drivers support anything above 9200. I never read big announcements on news pages about »free ati driver now supporting new card xy«. Now, if you have a look at the xorg-page, it doesn't even have release announcements. It looks boring. We know that xorg is cool, that it has wobbly windows and such, that development is happening. But looking at the webpage, it much more looks like xfree86.

This problem is not just related to xorg, it's just that I noticed this fact the last days (two driver-releases, only one noted). Same thing was e. g. with ffmpeg supporting h264 for a long time and then I read that some »I-forgot-their-name«-company said they'll bring a commercial h264-codec to linux. Or that about a week after ffmpeg supported wmv9 (also rarely noted by the public), real software said they want to bring wmv-support to linux. There's so much great stuff going on in free software development that would deserve more publicity.

Oh, and for a last note, Lars also has a nice example how not to do it.

If you've been surfing around the internet lately, you probably noticed that videos are often provided via some strange flash-players. That's ugly, because a) you can't download them and b) you need the proprietary flash-plugin. If you have a deeper look into how those flash-stuff works, it's basically just a small applet getting a flv-file (Flash Video) via http. Now, in theory you can use some sniffer like wireshark to get the url or directly the full video. But you'd still need to run the applet in some way.

But there are better solutions, at least for the most common service youtube (google video has recently added download links, so that's fine for now). The URLs are standardized and can be extracted from the page source.

Konqueror users can get this small extension, which will add a context menu for youtube under right click -> actions. Firefox-users can get VideoDownloader (which supports much more video platforms).
As Eiferer noted in the comments, VideoDownloader is SpyWare, so I'd suggest you don't use that. There's another one, based on greasemonkey, here, and, a platform independent bookmarklet here.

Now, playing flv is supported by ffmpeg, so all common linux-players should be able to play them. Thus you can get those videos and play them without using any proprietary software.

Thanks to Kostya, ffmpeg now supports the VC-1 codec, which is also used in Microsofts WMV9-format.

In the past, for Linux-users it was only possible to play those videos with win32codecs, which use proprietary windows-dlls and don't work on non-x86-platforms. With this improvement, one of the most common multimedia-formats unsupported by free software can now be played with all major free players (as ffmpeg is used by vlc, xine, mplayer, totem and many others).

Congrats to the ffmpeg-guys. The easiest way to get stuff playing is getting mplayer from svn (I used the mplayer-svn-ebuild from this Multimedia Overlay with some small modifications).

(via Breaking Eggs and making Omelettes)