VP8-RTP PictureID

[Jagadeeswaran R]

Hi All,

Is there any guideline on how to obtain or generate PictureID for VP8 RTP payload?

Is it to be obtained from VP8 Encoder or "RTP payload creator" module supposed to generate?

Appreciate any info that you can provide.

Regards,
Jagadeeswaran.R

[Jan Linden]

Hi,

In shor,t WebRTC is transparent to PictureID which is generated in the VP8 wrapper.

The guidelines for the generation of the pictureID are in the proposed VP8 RTP spec: 

 PictureID:  8 or 16 bits.  This is a running index of the frames.

      The field MUST be present if the I bit is equal to one.  The most

      significant bit of the first octet is an extension flag.  The 7

      following bits carry (parts of) the PictureID.  If the extension

      flag is one, the PictureID continues in the next octet forming a

      15 bit index, where the 8 bits in the second octet are the least

      significant bits of the PictureID.  If the extension flag is zero,

      there is no extension, and the PictureID is the 7 remaining bits

      of the first (and only) octet.  The sender may choose 7 or 15 bits

      index.  The PictureID SHOULD start on a random number, and MUST

In addition, an implementation of the pictureID generation and extraction may be found in the VP8 wrapper (encoder and decoder respectively), which can be found in src/modules/video_coding/codecs/main/source/vp8.cc. 

Thanks,

Jan.

[Jagadeeswaran R]

Hi Jan, Thanks for your reply.

Regards,
Jagadeeswaran.R