AC3 issues.... But AC3 patent from Dolby expired

#1
Hi,
first thank you for providing such great software, thats really great!!!

I saw, that many Android users have AC3 issues, and I understand, why,
I also have these issues, even I have the AC3 codec on my Android box.

However, the patents from Dolby for AC3 expired in 2017, so it should be possible to add AC3 support without any cost,
Please check this link:
https://www.cnx-software.com/2017/02/10 ... ry-1-2017/

With that in mind, would it not be possible to add AC3 support in the Android version? Perhaps paid in Play Store? Or crowd funded? I assume there should not be any licence payments anymore, since the patent expired...

Thanks,
Super3000

Re: AC3 issues.... But AC3 patent from Dolby expired

#3
Hi, Prog, thanks for your reply.

Yes, there are free apps which decode AC3 for free: VLC for example (see below), AC3 video player etc...
There are also free libraries for AC3 decoding (see below).

The patent expired for the whole world as far as I know:

https://web.archive.org/web/20170401170 ... omday.org/

There is stated:

Developers
When would I need to decode AC-3?

Playing most live TV content
Playing most recorded TV content
Playing many videos from DVD
Playing many videos from Blu-Ray
Playing videos recorded by some digital camcorders
Playing some online streaming content offered in 5.1 surround sound

When would I need to encode AC-3?

Hopefully never! In practice, there are a few cases: [removed]

Is AC-3 any good? Should I use it for new stuff?

No, of course not. AC-3 is over 25 years old and horribly inefficient.

How can I safely use AC-3 in my app?

There are multiple open source implementations of the AC-3 encoder and decoder. Some general guidance:

Remove any code that encodes, decodes, parses, muxes, or demuxes E-AC-3 ("Dolby Digital Plus"), MLP, or TrueHD. These are still covered by several patents.
Avoid using trademarks such as "Dolby Digital" in your user interface, support articles, app description, and marketing materials. Use the generic terms "AC-3" or "A/52" to refer to the audio technology.

The following open source libraries implement AC-3:

libavcodec in ffmpeg (LGPLv2.1+) and libav (LGPLv2.1+)
Decoder and encoder for AC-3
To compile only the AC-3 decoder: --disable-everything --enable-decoder=ac3 --enable-demuxer=ac3 --enable-parser=ac3 (then enable other parsers, demuxers, muxers, decoders, and encoders that you need)
To compile the AC-3 decoder and the AC-3 encoder: --disable-everything --enable-encoder=ac3 --enable-decoder=ac3 --enable-muxer=ac3 --enable-demuxer=ac3 --enable-parser=ac3 (then enable other parsers, demuxers, muxers, decoders, and encoders that you need)
Warning: When preparing to use libavcodec in any product, you should always start by disabling all encoders, decoders, parsers, muxers, demuxers, bitstream filters, protocols, filters, and hwaccels, then selectively enabling the ones that your product absolutely needs. To do this, use --disable-everything as your first ./configure option. This will help protect your product from unnecessary intellectual property disputes as well as some security vulnerabilities. If you have not added --disable-everything as your first option, you should at least manually disable the encoders, decoders, muxers, demuxers, and parsers for eac3, mlp, and truehd.

liba52 (GPLv2) used by VLC and others
Decoder only for AC-3

valib from AC3Filter (GPLv2)
Decoder and encoder for AC-3. Note: Build process does not allow easy removal of patented E-AC-3 code.

Re: AC3 issues.... But AC3 patent from Dolby expired

#11
Hi, Prog,

I tested four apps with IPTV AC3 Streams from Play Store, ALL apps work OK with AC3
(and ProgTV Android has no sound with these streams)

Here are the links to Google Play:

1. IPTV Player from Alexander Sofronov:
https://play.google.com/store/apps/deta ... droid.iptv

2. Smart IPTV Player :
https://play.google.com/store/apps/deta ... er.android

3. GSE Smart IPTV:
https://play.google.com/store/apps/deta ... .smartiptv

4. and some time ago I also tested Perfect Player from niklabs:
https://play.google.com/store/apps/deta ... niklabs.pp

I tested only Google Play without payment, only free apps.
cron