Exported M4A file contain zero data

[Gale Andrews]

Made a boob... but got the understanding now and all is well.

Thank you very much for your guidance and instruction.

That is OK, I made it clearer in my post that the file name chosen for export should be typed in the export dialogue as normal, not in the command.


Gale

[luisppk]

Hi, I'm here 'cause I also have an issue with audacity converting a 6ch DTS audio to a 6ch aac.

I prefer to explained visually, so I capture an image of what I'm doing and the problem itself.
Please take a carefully look to the link (click once on image and then select 'View raw image' to expand).

http://i64.tinypic.com/2a66z5x.jpg

Image detail:
1. This is the audio I have. A 6 channel dts. I want to convert it to a 6 channel 192kb aac.
2 & 3. The options I assign in audacity.
4. Final message.

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I tried to download and reinstall ffmpef... No result.
Tried to change to 320kb instead of 192... no result.

Any ideas what is going wrong?

[Gale Andrews]

Hi, I'm here 'cause I also have an issue with audacity converting a 6ch DTS audio to a 6ch aac.

I prefer to explained visually, so I capture an image of what I'm doing and the problem itself.
Please take a carefully look to the link (click once on image and then select 'View raw image' to expand).

http://i64.tinypic.com/2a66z5x.jpg

Image detail:
1. This is the audio I have. A 6 channel dts. I want to convert it to a 6 channel 192kb aac.
2 & 3. The options I assign in audacity.
4. Final message.

-------

As explained a few posts above ( http://forum.audacityteam.org/viewtopic ... 27#p293427 ) the "M4A (AAC) Files (FFmpeg)" item only exports maximum two channels because the "libvo-aac" encoder it uses is limited to two channels. Follow the steps in http://forum.audacityteam.org/viewtopic ... 27#p293427 to choose "(external program)" instead of "M4A (AAC) Files (FFmpeg)" and type out a command that tells Audacity to use the native FFmpeg encoder instead.

Due to another problem, the quality control after opening the "M4A (AAC) Files (FFmpeg)" item does not change the quality, but you can specify the quality when you use the native FFmpeg encoder at the command-line.

Gale

[luisppk]

Seems to me that 'libvo-aac' is full of problems... why is it used in audacity?
Despite the reasons you have to use this encoder, will be better if you put some advice (or warning) in the 'help' section. Also, audacity must no show options can't work (image 3).
From my point of view, I strongly recommend you to change that encoder. The faster, the better.

Thanks for your program, I'll use it when having audios different from 6ch (or more).

[Gale Andrews]

Seems to me that 'libvo-aac' is full of problems... why is it used in audacity?

Because that is the encoder that is used by the group that build the FFmpeg libraries for Windows that we recommend. They are the only group I am aware of who offer pre-built FFmpeg for Windows.

All the AAC encoders have some problem or weakness where they are not as good as the others: https://trac.ffmpeg.org/wiki/Encode/AAC.

will be better if you put some advice (or warning) in the 'help' section.

Yes I have made a note to look into that.

audacity must no show options can't work (image 3).

That would be a (low priority) but probably quite involved programming task. Generally Audacity does not know whether the encoding will succeed until it tries it, and when it fails it does give an error message.

If a later version of libvo-aac supported more than two channel export, then Audacity would have to check the FFmpeg version in use in order to throw a warning before trying to encode.


Gale

[luisppk]

ok, good luck Gale.

Luis

[swaan]

Very useful thread!

If you got ffmpeg error 2 like I did then you need to supply the whole path to ffmpeg on the command line.