5.1 to 2.0 Audio

[Anakin]

Hey guys!

I know this might seem like a silly question, and I think I know the answer, but I just want to ask anyway to clear things up.

I have a ripped video that only has a 5.1 audio track. I want to convert it to a smaller file size and only 2 audio channels to put on my daughter’s tablet. I am using TMPGenc Mastering Works to convert. If I just select stereo, will it just take the left and right channels or somehow mix the 5 channels into stereo?

Thanks guys!

Ani

[codemaster]

The video player app on the tablet, will take the 5.1 audio, and make it 2.0 while it plays the video. Therefore, it is easier if you let it as it is, than to change it. You can make the video smaller while keeping audio untouched.

[Cornucopia]

Not all player apps properly support downmixing, @codemaster, so I'm not sure that's the best advice.
Also, in general, 2.0 streams ARE smaller than 5.1 streams, assuming similar bitrate per channel (even including interchannel savings).


Scott

[ProWo]

Use my clever FFmpeg-GUI.
This has a special setting (channels 5.1 to 2) that optimizes the downmix so that the voices are slightly amplified in relation to the background audio, giving a better listening impression than a simple downmix.

[LigH.de]

In addition to ^ ProWo's suggestion:

A long time ago, BeSweet used to be the preferred tools to downmix audio; it supported several audio decoders and encoders and different matrices with Dolby ProLogic and ProLogic-II. Today it may be hard to get it running with a GUI (I believe it was based on Visual Basic runtimes). Similar in features was HeadAC3he, it even supported some lossless AC3 cutting. But the Aften AC3 encoder was a bit limited in quality.

A comparable more modern tool is BeHappy which uses AviSynth and several audio source plugins. Also useful: fre:ac, MeGUI and Hybrid.

[butterw]

aac stereo audio in mp4 container has the best compatibility. The recommended encoder is libfdk_aac (with a bitrate of 64kbps per channel, or more).

Downmixing can be done in a number of apps (and some offer different output modes: Stereo, Dolby ProLogic and ProLogic-II), but not all come with libfdk_aac.

In Avidemux, you set the the audio output to AAC(FDK) and select the desired remix mode in filter settings.

[LigH.de]

Some newer tools also support the Apple QuickTime AAC encoder (qaac - which requires iTunes installed or the CoreAudio DLLs getting extracted from its installer), which has also a superior quality in "True VBR" mode.

[hello_hello]

The portable version of foobar2000 I uploaded last year includes lots of encoder presets for converting just about any audio format to just about any other audio format, and it also includes "downmix to stereo" conversion presets.

https://forum.videohelp.com/threads/396860-foobar2000-portable-%28for-audio-encoding%29