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ffmpeg: Free Software's WMA decoder
mmu_man writes "This morning, after the usual spams, I got this from the ffmpeg-devel mailing list:
Here it is, something we waited for long. Now we have a FreeSoftware (LGPL) WMA (Windows Media Audio) decoder. WMA is the highly proprietary audio codec M$ is pushing along with its user-locking tools like DRM. this will free us from the ugly DLL hacks required to play DivX until now.
Note there isn't any encoder yet, but who would like to encode into WMA while we have better and more open solutions?
With this new codec, ffmpeg really proves itself as the most complete audio/video grabbing, convertion and streaming solution, for Linux, but also FreeBSD, Windows and even BeOS. Note ffmpeg codecs are used in a lot of other FreeSoftware projects, like mplayer."
Also interesting is the ad I just saw for Helix(RealPlayer) and their version of Open Source code. Here's the link.
...MS decide this is illegal and start suing? I mean, clearly there's the whole DMCA thing. Does this decoder ignore MS's DRM system? I would have read the article, but I don't speak C...
Real Daleks don't climb stairs - they level the building.
Sure, I'm all in favour of being able to play more movies on my linux system - even though I'm unlikely to own (m)any wmv movies...
But my question is how legal is this?
What is to stop MS attacking open source in the same way as RIAA attacked - and closed - napster?
yes, yes, one is a concept, the other is a program - but RIAA wants to make ANY file sharing program which is similar to napster illegal, and their certainly making progress toward that goal...
If a percentage of open source developers ignore the law - such as a percentage of napster users did - whats going to happen in the future?
I remember someone mentioning in an earier discussion that the WMA encoder fooled many people into thinking their encoded audio sounded "better" by applying a compressor/dynamics (6:1 ratio was it?), leaving the dynamic range 'squished' and making music sound louder (which isn't really "better"). Can anybody confirm this?
If an open version of a WMA encoder is released, it would be interesting to see how it would perform versus the MS encoder in this respect.
--
Maciek
-- Maciek
Very simple. DivX uses an audio codec to encode audio. A large number of DivX files use mp3 for audio (ogg is also possible, though not many players support it), and the rest use wma. Now, you won't need the /usr/lib/win32 directory full of Microsoft DLL's in order to play those Invader Zim episodes encoded using wma audio, assuming players take up this code. You could always re-encode them into mp3 audio at a greater loss of quality, but I like this solution better.
Is your browser retarded?
Can this source code be subjected to DMCA?
Can its author be sued for reverse engineering?
Is it planned that DRM features will be added at some point, or the above applies..
have you been defaced today?
This is presumably a decoder compatible with the classic "WMA" codec. This bitstream was locked down with WMA2, although they have made progressive enhancements to the encoder all the way through WMA9. It's really a very good codec for stereo 44.1 16-bit kinds of applications.
.wma files out there today, although that percentage might start dropping as WMA9 Pro gets traction. It is certainly a welcome effort!
Not that there are two NEW WMA codecs introduced in Windows Media 9 that aren't backwards compatible.
WMA 9 Professional aims for higher bitrates (48-768 Kbps) and multichannel (stereo with matrixed support or six discreet channels). And it can do deeper than 16-bit. If the old WMA was a competitor to MP3, WMA9Pro is a competitor to AC-3/Dolby Digital. And like WMA v. MP3, it has about a 50% advantage on compression efficiency.
There is also WMA9 Voice, which is a really good narrowband codec. Despite its name, it does a surprisingly good job with music as well. It operates from 4-20 Kbps.
WMA9 Voice is replacing the ACELP.net voice codec, which Microsoft licensed binary code for, but doesn't have the source code. Thus they couldn't get it for MacOS X or PocketPC.
Anyway, this decoder should handle 95% of the
My video compression blog
"With this new codec, ffmpeg really proves itself"
:-)
Surely this is a "dec", not a "codec". A codec is a Coder/Decoder, and what they've got here is just a Decoder
If intelligent life is too complex to evolve on its own, who designed God?
I presume this is a sign that .avi files with wma or ABR mp3 tracks, or maybe ac3 tracks are pretty much entrenched now in terms of market? First mp3 becomes entrenched and now this? .avi is a poor container format (vbr prohibited, for example). DivX is decent, but not really a 'standard'. It may be MPEG-4 compatible/complete (I have no idea), but the FourCC code on those files is 'DIVX', and that represents a non-standard approach. Of course, the FourCC is only relevant in .avi and something easily faked in alternative encoders, but it just irks me...
.Ogg container over .avi, or quicktime, or, best yet, the official standard container format of MPEG-4 (which, if not identical, is highly similar to quicktime 6 and/or the .divx format (does anyone use that at all?). Was there an audio MPEG-4 codec to go with the video and container, or would Vorbis audio be the best option?
And CBR mp3 audio... ick... maybe it replicates the bug and plays VBR mp3 audio, but still, doesn't mp3 only support two channels?
I would love to see the proliferation of something much more elegant. Say 'MPG4' FourCC (if you must).
XML is like violence. If it doesn't solve the problem, use more.
The project from what I see is mostly (if not all) done by non-Americans. So the DMCA does not apply to these people, nor to more than 99% of the countries in the world.
Sure, it's hosted on sourceforge servers, which I assume is located in the US, but hosting can be obtained elsewhere just as easily.
So quit naysaying and just accept the fact that not every open source project is an attempt to defile MS's (or the American legal system's) supremacy.
Welley Corporation - SLM Scammers
I'm sure I remember a /. article from someone who was closed down by Microsoft (read: sent threatening letters) for attempting to produce a WMA decoder. The argument then was that the WMA format was covered by various patents.
What's to stop the same thing happening to this one?
Only DivX 3.11 was a hacked Microsoft coded.
4.0 and onwards were developed from scratch.
Are they sure that this isn't covered by a patent? I remember almost two years ago that VirtualDub had to remove support for ASF files because Microsoft had a patent on some part of it. The VirtualDub guys just removed support rather than fight MS. I hope this doesn't turn out to be the same situation.
Prevent email address forgery. Publish SPF records for y
Athletic Scholarships to universities make as much sense as academic scholarships to sports teams.
The only pitty is that there are no real stable interfaces to the library, which makes a lot of projects to statically link the libraries :(
:X Oh well, that's what makes life (and coding) interesting of course ;) -and trying to capture possible problems with m4 macros >:)-
We changed the upstream sources a bit to provide libavcodec and libavformat as shlibs and started using dynamic linking.
As long as ppl use the sources provided with the debs and compile, no problem, but it's hacking time again when someone gets a CVS release
Genius doesn't work on an assembly line basis. You can't simply say, "Today I will be brilliant."
The key difference is that it would be a good thing for the Ogg Vorbis format to spread and become as widely used as possible. Nobody really wants to sees WMA become any more popular; it's best to just offer basic functionality for *nix systems that wouldn't otherwise have it. It's a tight balance: trying to make the free system better without giving any more power to the secret format gods.
314-15-9265
DivX has nothing to do with WMA. DivX is a video codec, WMA is an audio codec. ;-) (with the smiley, also known als DivX 3.11) was a hacked version of MSMPEG4v3 (there were also hacked versions of MSMPEG4v2 around, but they aren't called DivX and are incompatible with v3). Although MS calls it "MPEG4vX", they are really incompatible with MPEG 4.
DivX
AVI has also nothing to do with DivX and WMA, it's just a container format. It just happens that some AVI files contain DivX video and WMA audio, but it may just as well be Indeo video with MP3 audio or whatever. You can put video and audio made in almost any codec in an AVI container.
Because DivX and WMA have nothing to do with AVI, you can, for example, also create Ogg files that contain DivX video with MP3 audio, Theora video with WMA audio, etc.
AVI is old, very old, and it should be replaced. No error detection, not streamable, difficult to support VBR codecs, etc. I hope one day, people will just stop encoding AVI files and switch to Ogg for MCF instead.
As mentioned elsewhere in this topic, the fact that the CODEC mentioned here is licensed under the LGPL is likely to prevent its use in players for some operating systems, which is a shame. Whether or not we like Microsoft or Windows Media, I think you'll agree that all authors of players, and all end users, should be able to play streams that are encoded in that format.
ffmpeg is great for video streams, and even sound streams. Just don't try doing both at once.
I have had *zero* luck trying to get the audio track to sync with the video, even at insanely low resolutions (eg half PAL) with no frame drop. Different combinations of different codecs make little difference it seems.
The FAQ even says so:
4) I get audio/video synchro problems when grabbing.
Currently, the grabbing stuff does not handle synchronisation
correctly. You are free to correct it. It is planned to fix it ASAP
So IMHO, ffmpeg as it stands is completely useless as an audiovisual grabber.
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife