OpusTodo: Difference between revisions

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== 1.1-beta ==
== For 1.2 ==
 
* Low bitrate quality improvements
* Vary tf_analysis end band based on complexity
* AVX optimizations
* Use pitch down to complexity 4 instead of 5?
* Fix compilation as a single module for gecko
* Testing


== Spec ==
== Spec ==
* Ogg mapping. See [[http://tools.ietf.org/html/draft-ietf-codec-oggopus IETF draft]]
* Matroska mapping. See: [[MatroskaOpus]] And firefox/ffmpeg implementation
* Matroska mapping. See: [[MatroskaOpus]]
* RTP payload format. Mono/stereo mapping is complete [[https://tools.ietf.org/html/rfc7587 RFC 7587]], no multichannel mapping yet.
* RTP payload format See [[http://tools.ietf.org/html/draft-spittka-payload-rtp-opus IETF draft]]
* mp4 mapping. See [[https://opus-codec.org/docs/opus_in_isobmff.html ISO Base Media File Format draft]]


== Website ==
== Website ==
* De-uglify webpage - some suggestions: write about codecs obsoleted by OPUS (Speex, CELT, Vorbis(?), and the prop. ones), write about implementations (is there only one so far?), comparison table (Opus, Vorbis, Speex, ..., MP5) of features (channels, freq, bits per sample, license, language (C89), integer impl. (Vorbis decoder only, Opus YES, ...), future use in video files (Theora? Dirac? WebM? other future codecs...), audio files for storage (like Vorbis, no raw Opus defined, only inside OGG), ...  
* De-uglify webpage - some suggestions:
* Promotional material (some nice free or Public domain sounds in Opus format)
** write about codecs obsoleted by OPUS (Speex, CELT, Vorbis(?) and the proprietary ones)
** write about implementations (libopus encoder/decoder, libavcodec decoder, any others?)
** [https://en.wikipedia.org/wiki/Comparison_of_audio_coding_formats audio codec comparison table] (Opus, Vorbis, Speex, ..., MP5) of features (channels, freq, bits per sample, license, language (C89), integer impl. (Vorbis decoder only, Opus YES, ...)
** future use in video files (Theora? Dirac? WebM? other future codecs...)
** audio files for storage (like Vorbis, no raw Opus defined, only inside OGG), ...  
* Promotional material (some nice free/public-domain sounds/radio stations in Opus format)


== Other ==
== Other ==
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== Opus-tools ==
== Opus-tools ==
* Port opusdec to libopusfile/libopusurl.
* A simple real time streaming example tool
* A simple real time streaming example tool
* Replaygain (half done— needs a gain tool)
** Start with opusrtp.c in [https://git.xiph.org/?p=opus-tools.git opus-tools]
** Make <code>opusrtp rtp://example.com:5431/</code> listen to that host and port and mux packets from there. Generalize the cpac bases --sniff implementation
** Make sending similarly generic. Maybe just <code>opusrtp source.opus -o rtp://example.com:5431/</code> to send source.opus out to the destination?
** Make --sniff save one file per
** Implement DTLS-SRTP. See webrtc.
** audio capture/encode, decode/playback?
** Parse and act on sdp for convenience and testing.
 
* EBU R128/Replaygain (half done— needs a gain tool)


== Surround work ==
== Surround work ==
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* Adaptive width narrowing and forced intensity stereo bands
* Adaptive width narrowing and forced intensity stereo bands


== Experiments ==
== Optimisations ==
 
* Vectorising comb_filter()
* Use 16-bit mul plus shift in denormalise_bands()
* Optimise MDCT somehow


* Test exp_analysis and void_my_warranty.patch
== Third-Party tool enhancements ==
* mutagen: [https://bitbucket.org/lazka/mutagen/issue/202/oggopus-support-in-place-rewrites-for support padding in comments header], [https://bitbucket.org/lazka/mutagen/issue/203/oggopus-allow-updating-the-output_gain allow updating output gain in ID header]


== Future work ==
== Future work ==
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* Save some float<->int conversions
* Save some float<->int conversions
* Improvements to LP mode CBR (greg has some code)
* Improvements to LP mode CBR (greg has some code)
* Unconstrained SILK VBR
* Better handling for the case where FEC has a different bandwidth than the current mode
* Better handling for the case where FEC has a different bandwidth than the current mode
* PLC transitions on unprotected SILK-SILK bandwidth changes?
* PLC transitions on unprotected SILK-SILK bandwidth changes?
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** find optimal switching time (low energy/tonality)
** find optimal switching time (low energy/tonality)
* Improve variable frame size
* Improve variable frame size
[[Category:Opus]]

Latest revision as of 18:59, 19 July 2016

For 1.2

  • Low bitrate quality improvements
  • AVX optimizations
  • Fix compilation as a single module for gecko

Spec

Website

  • De-uglify webpage - some suggestions:
    • write about codecs obsoleted by OPUS (Speex, CELT, Vorbis(?) and the proprietary ones)
    • write about implementations (libopus encoder/decoder, libavcodec decoder, any others?)
    • audio codec comparison table (Opus, Vorbis, Speex, ..., MP5) of features (channels, freq, bits per sample, license, language (C89), integer impl. (Vorbis decoder only, Opus YES, ...)
    • future use in video files (Theora? Dirac? WebM? other future codecs...)
    • audio files for storage (like Vorbis, no raw Opus defined, only inside OGG), ...
  • Promotional material (some nice free/public-domain sounds/radio stations in Opus format)

Other

  • Oggz-validate (should also validate opus toc)

Opus-tools

  • Port opusdec to libopusfile/libopusurl.
  • A simple real time streaming example tool
    • Start with opusrtp.c in opus-tools
    • Make opusrtp rtp://example.com:5431/ listen to that host and port and mux packets from there. Generalize the cpac bases --sniff implementation
    • Make sending similarly generic. Maybe just opusrtp source.opus -o rtp://example.com:5431/ to send source.opus out to the destination?
    • Make --sniff save one file per
    • Implement DTLS-SRTP. See webrtc.
    • audio capture/encode, decode/playback?
    • Parse and act on sdp for convenience and testing.
  • EBU R128/Replaygain (half done— needs a gain tool)

Surround work

  • Apply spreading to energy masking
  • More conservative energy masking (not just mean difference) and dynalloc
  • Allow SILK/hybrid on center channel for voice?

Psychoacoustic stuff

  • Adaptive width narrowing and forced intensity stereo bands

Optimisations

  • Vectorising comb_filter()
  • Use 16-bit mul plus shift in denormalise_bands()
  • Optimise MDCT somehow

Third-Party tool enhancements

Future work

  • psymodel based VBR
  • Remove copy in inverse MDCT
  • Save some float<->int conversions
  • Improvements to LP mode CBR (greg has some code)
  • Unconstrained SILK VBR
  • Better handling for the case where FEC has a different bandwidth than the current mode
  • PLC transitions on unprotected SILK-SILK bandwidth changes?
  • Figure out how to use speech/music detection optimally
    • find optimal switching time (low energy/tonality)
  • Improve variable frame size
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