[vlc-devel] Re: [BUG] wrong IOD_descriptor coding

Nico Sabbi nsabbi at tiscali.it
Sun Mar 20 00:59:10 CET 2005


Nico Sabbi wrote:

>
> Hi,
> reading the specs of the IOD descriptor I found what VLC is 
> m[ie]ssing: the Scope of IOD label
> (1 bytes just before the IOD_label)
>
> I also know why: it's absent in the draft floating around, but defined 
> in the final specs.
>
> This is how it should be coded:
> 0x10 indicates that the IOD_label is unique within the program
> 0x11 indicates that the IOD_label is unique within the transport stream
>
> Unfortunately this creates an incompatibility with every standard 
> compliant SL demuxer,
> so it has to be worked around, but I hope that future versions of VLC 
> will be fixed.
>
> Thanks,
>
>    Nico
>
>

I forgot to add that two more things in the TS muxer that, if my 
understanding of the specs is correct,
don't look good to me:

1) you always use pmt_stream_type 0x11 to identify AAC, but this value 
is valid only for
AAC in LATM transport syntax, instead I always see ADTS syntax for which 
is assigned
pmt_stream_type 0x0f

2) for mpeg4video / h264 you always use pes_id==0xfa and 
pmt_stream_type=0x10 / 0x1b,
but 0xfa is associated with pmt_stream_type 0x12 (SL or flexmux in PES) 
so IMHO
the correct ways to mux these video streams are (in exclusion)
a) drop SL (after all it's totally useless and complicated crap) and use
    pmt_stream_type=0x10 / 0x1b and pes_id == 0xCn
b) use SL as you do now and set pmt_stream_type=0x12

What's your opinion?

Thanks,

       Nico

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