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Cannot extract highest bitrate 151kbps AAC audio track

Jul 3, 2012 at 2:27 AM
Edited Jul 3, 2012 at 3:34 AM

Contains this Audio track:

Audio: aac, 44100 Hz, stereo, 151 kb/s [5,96 MB]

Which I can't select with youtubeFisher.


HQ track grabbed with youtubeFisher:

Audio: aac, 44100 Hz, stereo, 120 kb/s [5,03 MB]



I see the 1080p version also contains a 192 kb/s vorbis audio track. It would be nice if we could extract this one too with youtubeFisher.

Jul 3, 2012 at 5:06 AM

Thanks for your feedback.

I had a look at the video you mentioned in your post and I can see we currently have 2 missing formats; Full-HD WebM and some other 3gpp format. I'll add these 2 formats later today hopefully.

Can you specify which resolution contains the audio track you're talking about? This video has 3 flv formats, large (480p), medium (360p) and small (240p).

As you know, YouTubeFisher extracts audio from flv video formats only (using the fantastic FLV Extract code by J.D. Purcell); if you know a simple library/code which we can use to extract audio from WebM video formats, we are willing to consider it.

Jul 3, 2012 at 5:53 AM

The 151 kb/s AAC track is inside the WebM HD Video 720p version. Checked with 'ffmpeg -i input.webm'

You can extract it with 'ffmpeg -i input.webm -vn -acodec copy output.aac'

The 192 kb/s vorbis track is inside the Full HD 1080p mp4 version and can be extracted with 'ffmpeg -i input.mp4 -vn -acodec copy output.ogg'

Jul 4, 2012 at 9:41 AM

Thanks for your feedback.
However ffmpeg is a library based on libavcodec which uses internal codec to create/convert (not extract) the audio track from video...
So, we will consider all these things for a future software release...

Jul 4, 2012 at 11:08 AM

Unfortunately this inroduces a dependency to a component which isn't avavilable in every machine.

One of the main goals of this application is to be small, standalone and portable; having dependency on ffmpeg isn't in line with these goals.

However, I'll still see if it makes sense to add this feature and make it available if the user's machine has ffmpeg, but that's another story :)

In the meanwhile, if you came across a .Net library which does the extraction from WebM and MP4, let me know about it. It's more likely to find WebM library as WebM is just a container based on Matroska (both are open standards).

Jul 4, 2012 at 11:10 AM

By the way, I forgot to mention that YouTubeFisher was updated yesterday to suppor the 2 missing formats; Full-HD WebM and some 3gpp.

Jul 4, 2012 at 11:11 AM
Edited Jul 4, 2012 at 11:12 AM

Sorry; duplicate post :)

Jul 6, 2012 at 3:01 AM
Edited Jul 6, 2012 at 3:01 AM


Are you sure ffmpeg is altering the audio track with the options -vn -acodec copy ? If i'm correct '-vn' ignores video and '-acodec copy' allows to copy audio losslessly.

The filesize and crc of the .aac generated by ffmpeg (from the 480p .flv) and the one downloaded by youtubeFisher are also both identical.

Anyway, I hope you can add support for extracting AAC and Vorbis audio tracks from MP4 and WebM if the user's machine has ffmpeg.exe. Allowing to choose these formats with youtubeFisher if the it's detects ffmpeg.exe on startup. For now I think it's the only way to go for extracting audio from MP4 and WebM. I saw a Firefox Youtube plugin that does something similair. By default it only allows downloading video, but when it detects ffmpeg it can also extract or convert the audio.

Jul 6, 2012 at 9:58 AM

You're right, for some formats and with those options, ffmpeg extract audio likes youtubeFisher.
Thanks for feedback, we will evaluate your suggestions for future releases...