Opened 16 years ago

Closed 16 years ago

#599 closed enhancement (fixed)

Codec framework enhancement: Interaction with SDP

Reported by: nanang Owned by: nanang
Priority: normal Milestone: release-1.0-rc1
Component: pjmedia Version: trunk
Keywords: Cc:
Backport to 1.x milestone: Backported:


  1. Type of attributes
    • ptime. Some codecs want to signal ptime, but this may not the best mechanism to use since ptime applies to the whole stream.
    • maxptime. Currently is signaled by AMR. Example:
    • fmtp. Examples:
      a=fmtp:18 annexb=no
      a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2; mode-change-neighbor=1
      a=fmtp:101 bitrate=24000
  1. Encoding offer:
    • initial offer should encode codec settings/preference
    • subsequent offer should encode the setting of current codec instance (?)
  1. Feature/format negotiation in negotiator. Example:
    • fmtp: to negotiate bitrate for some codecs (e.g. G.722.1, SIREN, etc):
      a=fmtp:101 bitrate=24000"
  2. Processing answer

Change History (2)

comment:1 Changed 16 years ago by nanang

In r2236:

  • Added "dec_fmtp" and "enc_fmtp" fields to pjmedia_codec_param.setting.
  • Codec factory puts its default parameters in "dec_fmtp" field.
  • pjmedia_stream_info_from_sdp() puts the "fmtp" attribute in SDP to pjmedia_codec_param.
  • Special treatment for fmtp "bitrate" parameter (of G722.1) during SDP negotiation
  • Added maxptime field in stream_info.
  • Replaced iLBC's fmtp "mode" implementation to use general fmtp mechanism.
  • Added some test scripts for G722.1 bitrate negotiation.

comment:2 Changed 16 years ago by bennylp

  • Resolution set to fixed
  • Status changed from new to closed

Done, closing the ticket.

Note: See TracTickets for help on using tickets.