OpusTodo

For 1.2

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

Spec

• Matroska mapping. See: MatroskaOpus And firefox/ffmpeg implementation
• RTP payload format. Mono/stereo mapping is complete [RFC 7587], no multichannel mapping yet.
• mp4 mapping. See [ISO Base Media File Format draft]

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

• mutagen: support padding in comments header, allow updating output gain in ID header

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