[FFmpeg-devel] [PATCH] libavcodec/mpeg12dec.c: rename 0x0502 CC format

[Soft Works]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Marth64
> Sent: Sunday, January 26, 2025 1:14 AM
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH] libavcodec/mpeg12dec.c: rename
> 0x0502 CC format
> 
> > they are broadcasting using a variation of DVB-S (there is no US
> standard for sat tv), so the current naming is actually valid.
> 
> This is my understanding also, but I do believe there was 1 other
> network that used the same variation.
> Hence why I suggested a generic name. The counter argument from
> Kieran
> was that it's not a DVB standard either so DVB 0502 not a great name.

It's "user data", so there doesn't necessarily need to be a standard. It's inconsistent anyway:

SCTE-20 (5.7) defines a single byte:

"user_data_type_code—An eight-bit code for picture user data, 0x03"

while ATSC/A53-Part 4 (6.2.3) mandates a 

"user_data_identifier – This is a 32 bit code"

Which is supposed to be registered with SMPTE:

https://web.archive.org/web/20150324170029/http://www.smpte-ra.org/mpegreg/mpegreg.html

Then followed by 03 as type code.

(this aligns with the implementation)


I haven't found the corresponding in the DVB specs, it must have a different name there.

sw