[Linux-kernel-mentees] ffmpeg s302m: are packets really encoded in biphase mark code?

[Daniel W. S. Almeida]

Hello!

I am trying to write a simple SMPTE 302M encoder in order to carry PCM 
audio data into a MPEG transport stream.

I noticed that AES3 uses biphase mark code for frames, except for the 
frame preamble, but SMPTE 302M makes no mention of biphase mark code 
whatsoever.

Looking at libavcodec/s302m.c, it is not clear to me whether any BMC 
decoding is taking place. I could not figure it out by looking at the 
encoder at libavcodec/s302menc.c either.

Therefore, my question is: am I required to encode frames using BMC if I 
want to decode them using ffmpeg?

(On a side note: what is ff_reversed used for in this codec?)

Thank you for your time!