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Is it possible to disable VP8 error concealment for WebRTC?

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  • Ultima risposta di Robert Kirnum

Robert Kirnum
Robert Kirnum
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Chrome appears to disable VP8 error concealment when rtcp-fb nack is negotiated when setting up a connection (SIP / SDP). I have not been able to get Firefox to disable error concealment. I am also unable get Firefox to enable rtcp-fb nack though I am not certain this will disable VP8 error concealment as on Chrome.

Chrome appears to disable VP8 error concealment when rtcp-fb nack is negotiated when setting up a connection (SIP / SDP). I have not been able to get Firefox to disable error concealment. I am also unable get Firefox to enable rtcp-fb nack though I am not certain this will disable VP8 error concealment as on Chrome.

Soluzione scelta

From http://www.ietf.org/rfc/rfc2327.txt SDP: Session Description Protocol

6. SDP Specification

… 

  Text records such as the session name and information are bytes
  strings which may contain any byte with the exceptions of 0x00 (Nul),
  0x0a (ASCII newline) and 0x0d (ASCII carriage return).  The sequence
  CRLF (0x0d0a) is used to end a record, although parsers should be
  tolerant and also accept records terminated with a single newline
  character.  By default these byte strings contain ISO-10646
  characters in UTF-8 encoding, but this default may be changed using
  the `charset' attribute.

Looks like the Firefox SDP parser requires a carriage return ('\r'), it is unable to process attributes ending in just a newline ('\n'). I guess the RFC does indicate SHOULD as opposed to SHALL.

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cor-el
cor-el
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Maybe check out the Firefox source code about rtcp-fb nack.

Modificato da cor-el il

Robert Kirnum
Robert Kirnum Utente che ha posto la domanda
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Soluzione scelta

From http://www.ietf.org/rfc/rfc2327.txt SDP: Session Description Protocol

6. SDP Specification

… 

  Text records such as the session name and information are bytes
  strings which may contain any byte with the exceptions of 0x00 (Nul),
  0x0a (ASCII newline) and 0x0d (ASCII carriage return).  The sequence
  CRLF (0x0d0a) is used to end a record, although parsers should be
  tolerant and also accept records terminated with a single newline
  character.  By default these byte strings contain ISO-10646
  characters in UTF-8 encoding, but this default may be changed using
  the `charset' attribute.

Looks like the Firefox SDP parser requires a carriage return ('\r'), it is unable to process attributes ending in just a newline ('\n'). I guess the RFC does indicate SHOULD as opposed to SHALL.