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Old 17th January 2019, 13:47   #1  |  Link
hajj_3
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Dolby AC-4 decoding support?

It seems as though vlc player and mpc-be do not support Dolby AC-4. From reading Dolby's own website (https://dolbyac4.com/uk/) it appears that U.K free-to-air satellite platform 'Freesat' has picked AC-4 as the exclusive next gen audio format for their 3rd generation satellite boxes that will be released this year. Therefore AC-4 broadcasts will likely happen this year not just a trial. It would be nice if FFmpeg/vlc/mpc-be added support to decode this audio codec. Does anyone know if work is being done in any of these to add support?
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Old 27th January 2019, 22:23   #2  |  Link
hajj_3
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I found this, not sure if it will be helpful for us: https://github.com/DolbyLaboratories/dlb_mp4base
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Old 28th January 2019, 08:55   #3  |  Link
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Quote:
Originally Posted by hajj_3 View Post
I found this, not sure if it will be helpful for us: https://github.com/DolbyLaboratories/dlb_mp4base
Not helpful. That's an MP4 muxer, not an AC-4 decoder. This PDF file might be useful, assuming there exist capable developers interested in transforming the specs into a functional decoder :-/
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Old 20th February 2019, 22:37   #4  |  Link
nevcairiel
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Some work for FFmpeg to support AC-4 decoding has begun. When it'll be complete and/or usable .. we'll see.
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Old 21st February 2019, 01:20   #5  |  Link
hajj_3
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Some work for FFmpeg to support AC-4 decoding has begun. When it'll be complete and/or usable .. we'll see.
nice

I can't seem to find any .AC4 sample audio files on the internet though which is annoying.
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Old 28th February 2019, 18:53   #6  |  Link
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If anyone has any AC-4 samples, that would be helpful for development. Preferably real-world samples, the commonly found ones in the DASH test suite etc, we already got.
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Old 2nd March 2019, 02:19   #7  |  Link
nussman
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Some dvb broadcaster are sending ac4:
https://www.dvbviewer.tv/forum/topic...4-sound-track/

I can ask for a sample if it helps.
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Old 2nd March 2019, 09:23   #8  |  Link
nevcairiel
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Already got some from the DVBViewer people, was hoping for more alternative samples to cover as much as possible, but thanks!
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Old 4th March 2019, 12:27   #9  |  Link
hajj_3
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Originally Posted by nevcairiel View Post
Already got some from the DVBViewer people, was hoping for more alternative samples to cover as much as possible, but thanks!
Please send all of your AC-4 samples to the developer of mediainfo, he wants some to add detection support: jerome@mediaarea.net
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