audio_descriptor: encoder writes 12 bits, decoder expects 8 bits

[tomstolarczuk]

In pkg/scte35/audio_descriptor.go, there’s a mismatch between how the encoder and decoder handle the audio_count and reserved fields.

During decode:

audioCount := int(r.Uint32(4))
r.Skip(4) // reserved

That reads 4 bits for audio_count and 4 bits for reserved (8 bits total).

During encode:

iow.PutUint32(8, uint32(len(sd.AudioChannels)))
iow.PutUint32(4, Reserved)

That writes 8 bits for audio_count and 4 bits for reserved (12 bits total).

That causes decode errors like:

audio_descriptor: buffer underflow

According to the SCTE-35 spec, audio_count is a 4-bit field, not 8.

[blahspam]

Thanks for the report. I should have a fix available soon.

[tomstolarczuk]

Thank you @blahspam