add compatibility flag

[tomjnixon]

Some systems produce files which don't work with the EAR currently, but could be made to work fairly easily.

We could add a a compatibility flag that enables some tweaks to the ADM before rendering. The same code/interface can be used in the renderer command and the ear-utils regenerate tool.

When the flag is used in the renderer, it should warn about non-compatibility and suggest using the regenerate tool.

The interface could be something like --compatibility=timing,dolby_speakerLabels, with a list of fix names to apply separated by commas. We should also add aliases which apply multiple fixes, and an all mode which does everything.

Proposed fixes:

• timing: same as --enable-block-duration-fix
• dolby_speakerLabels: apply a mapping to speakerLabels to turn RC_* to ITU labels
• extra_pack_ref: remove audioStreamFormat to audioPackFormat references to fix audioStreamFormat x has a reference to both an audioPackFormat and an audioChannelFormat error
• dolby: all 3 above fixes

It would be good to collect more information about how this should work:

• What speaker labels can exist, and what ITU labels should they be mapped to? I've used this before:

  RC_L: M+030
  RC_R: M-030
  RC_C: M+000
  
  RC_LFE: LFE1
  
  RC_Lss: M+090
  RC_Rss: M-090
  
  RC_Lrs: M+135
  RC_Rrs: M-135
  
  RC_Lts: U+090
  RC_Rts: U-090
  

• What fixes are required for different software? I don't have great visibility into this -- I seem to remember the pack reference thing not being required previously, but is for nuendo 11 files.

[masonyoungblood]

Hello! Is there any movement on getting around the "audioStreamFormat X has a reference to both an audioPackFormat and an audioChannelFormat" error?

[davemar-bbc]

Do your ADM files have both audioPackFormat and audioChannelFormat being referenced within the audioStreamFormat elements? If so, then those files are not compliant with the ITU BS.2076 ADM standard.
If you can't do anything about the software that's generated these ADM files, then one approach is to use the EBU ADM Toolbox (EAT) (https://github.com/ebu/ebu-adm-toolbox) to fix them. Within the EAT there's a config called 'fix_dolby' that corrects ADM files with this particular flaw in them.

[WernerBleisteiner]

Can second @davemar-bbc proposal. But mind, this is a one way track... There's no solution yet in sight, that Dolby fixes this - likely bug - from their early implementation of ADM.