[FFmpeg-devel] [PATCH 1/2] avcodec/s302m: enable non-PCM decoding

Gyan Doshi ffmpeg at gyani.pro
Tue Jan 23 13:18:06 EET 2024



On 2024-01-23 03:58 pm, Nicolas Gaullier wrote:
>> +#define IS_NONPCMSYNC_16(state)   ((state & 0xFFFF0FFFF0)     == NONPCMSYNC_16MARKER)
> Is this single 32 bits marker enough to avoid a fake detection ?

It will have to do. The modal number of payload packets expected in a 
single s302m packet is one, so there's no redundancy.
And since the AES3 sync (time slots 0-3) is stripped off (in all samples 
I have), we can't identify byte 0 of the channel status word for a 
double-check.

However, unlike s337m probe, which is dealing with data of unknown 
provenance, the context here is a PES packet emitted of a stream 
identified as s302m by the demuxer so the odds are low of a false positive.

Regards,
Gyan



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