Dolby Headphone encoding

[kilobulb]

As there seems to be a dearth of android video players with dolby headphone support I was looking at a way of encoding audio tracks to dolby headphone. It's been years since I've done any encoding so I'm not exactly current with modern options.

The goal is to reencode the ac3 and dts I have on current files to a stereo dolby headphone track and then add this to the mkv leaving the current video,audio and subtitles untouched. I can't seem to see any current all in one solution to do this or indeed encode to dolby headphone at all.

To mix to dolby headphone in Zoomplayer I currently use ffdshow to decode the audio and to swap the channels and then use cyberlink's powerdvd audio encoder as the dolby headphone dsp. I guess it would be possible to do something similar with graphedit to encode the output to mp3. But I think this would result in me having to mux the resulting mp3 back into the file. Ideally I want to find a process which would allow me to do this in bulk and as automated as possible.

Does anyone currently do anything similar? Any issues with audio sync?

[jman98]

I found the following thread elsewhere that might be of some use to you.
http://www.hydrogenaudio.org/forums/index.php?showtopic=39404&st=150&p=602907&#entry602907

The fact that I am really good at searching (you COULD have done that yourself) should NOT be interpreted to mean that I am some kind of Dolby Headphone expert (I am not) or that I have ever used the format or encoded to it (I have not).

[kilobulb]

I found the following thread elsewhere that might be of some use to you.
http://www.hydrogenaudio.org/forums/index.php?showtopic=39404&st=150&p=602907&#entry602907

The fact that I am really good at searching (you COULD have done that yourself) should NOT be interpreted to mean that I am some kind of Dolby Headphone expert (I am not) or that I have ever used the format or encoded to it (I have not).

Thanks for the link. I experimented with that foobar plugin a few years ago. It's sterling work by the developer but I didn't really care for the effect on stereo music and I didn't have any multi channel recordings at the time. I may revisit it to see if I like it better with my current lineup of headphones.

Unless I'm missing something it is however not of any use for simple reencoding of the audio of a mkv video file... As far as I am aware the foobar plugins are only useable in foobar? Can a foobar plugin be used outside of foobar? i.e. be registered as a filter in windows? If so I guess it could be used instead of the cyberlink filter and should save the need to swap the channels in a graphedit encode.

[kilobulb]

Unless I'm missing something it is however not of any use for simple reencoding of the audio of a mkv video file... As far as I am aware the foobar plugins are only useable in foobar? Can a foobar plugin be used outside of foobar? i.e. be registered as a filter in windows? If so I guess it could be used instead of the cyberlink filter and should save the need to swap the channels in a graphedit encode.

It appears foobar can be used to reencode audio but you have to extract it from the mkv and then remux it back in:
http://www.simplehelp.net/2008/11/06/how-to-use-foobar2000-to-convert-audio-files/

It seems that there's no tool that does this directly as i'm sure they'd advertise the fact. Strange given all the options for reencoding for portable devices. Presumably most people are using headphones so as not to impose on their fellow commuters. Dolby headphone seems a no brainier to me if you are going to using headphones for watching the video anyway.

[pandy]

As there seems to be a dearth of android video players with dolby headphone support I was looking at a way of encoding audio tracks to dolby headphone. It's been years since I've done any encoding so I'm not exactly current with modern options.

Hmm, Dolby Headphone is final stage for processing ie at the output You should have normal stereo track however optimal for binaural hearing. Personally i prefer ffdshow hrtf processing - seems to sound more "realistic" on headphones.

Even more advanced proccessing is possible with convolver (foobar, ffdshow).

[kilobulb]

Yup what I'm looking to do is take the result of the dolby headphone processing and encode it as a binaural soundtrack. I found ffdshow's hrtf pushed everything back and the dialog seemed funny. This however was with full size headphones and I believe it's meant for IEMs. I will however be using IEM's for listening to these encodes. I may have to do another comparison. Convolver looks very interesting I actually hadn't heard of it before. Looks like it can also be used for room eq.

For the moment the solution I'm using is encoding using the filter path in this graph:


And then using mkvtoolnix to mux the new dolby headphone mp3 track into the mkv. Not exactly an elegant solution but it does the job it appears. For some reason LAME audio encoder doesn't seem to follow the vbr profiles I set in graphstudio so I'm stuck using 320 CBR which seems excessive but I guess space is cheap these days.

For anyone who is interested in doing this you need to swap the channels as the Cyberlink decoder expects them differently to standard. I refer you to this thread on the zoomplayer forums for how to do so. Done correctly you should be able to encode dts, ac3 or any other surround format ffdshow can process to dolby headphone.

Edit: the result of the above:ac3test_dh2.mp3