[MPlayer-dev-eng] Can MPLAYER demux conveying a SL stream?

[Nico Sabbi]

Deckard wrote:

>Hello, Nico.
>
>There is definition of MPEG4-SL in ISO_14496-1.
>
>Flexible and configurable packetization facility that allows 
>The inclusion of timing, fragmentation and continuation information on
>Associated data packets.
>
>An SL-packetized stream consists of a sequence of packets, according to the syntax and semantics specified in 10.2, that encapsulate a single elementary stream. The packets contain elementary stream data partitioned in access units as well as side information, e.g., for timing and access unit labeling. SPS data payload enters the decoding buffers, i.e., the side information is removed at the input to the decoding buffers.
>
>class SLConfigDescriptor extends BaseDescriptor : bit(8) tag=SLConfigDescrTag {
>	bit(8) predefined;
>	if (predefined==0) {
>		bit(1) useAccessUnitStartFlag;
>		bit(1) useAccessUnitEndFlag;
>		bit(1) useRandomAccessPointFlag;
>		bit(1) hasRandomAccessUnitsOnlyFlag;
>		bit(1) usePaddingFlag;
>		bit(1) useTimeStampsFlag;
>		bit(1) useIdleFlag;
>		bit(1) durationFlag;
>		bit(32) timeStampResolution;
>		bit(32) OCRResolution;
>		bit(8) timeStampLength;	// must be  64
>		bit(8) OCRLength;		// must be  64
>		bit(8) AU_Length;		// must be  32
>		bit(8) instantBitrateLength;
>		bit(4) degradationPriorityLength;
>		bit(5) AU_seqNumLength; // must be  16
>		bit(5) packetSeqNumLength; // must be  16
>		bit(2) reserved=0b11;
>	}
>	if (durationFlag) {
>		bit(32) timeScale;
>		bit(16) accessUnitDuration;
>		bit(16) compositionUnitDuration;
>	}
>	if (!useTimeStampsFlag) {
>  
>

where are these 2 fields (durationFlag and useTimeStampsFlag) defined?
It seems they are only checked, but not set. Maybe they are missing in 
SL-in-PES streams?
Once I read of NULL SL packets in PES; are they packets with
the first bytes constantly set to a fixed value ?

>		bit(timeStampLength) startDecodingTimeStamp;
>		bit(timeStampLength) startCompositionTimeStamp;
>	}
>}
>
>
>I consider implementing mpeg4-sl depacketizer in MPlayer.
>If mplayer depacketize mpeg4-sl packet, it is possible to play DMB stream.
>I need help.
>
>What do you think of that?
>
>  
>

it seems it can work, but I have 2 question:
- in these streams, are timestamps conveyed in PES headers (as I hope, 
it seems
to be the only reasonable option) or in SL headers?
- the PMT stream_types involved is 0x12, right? (discarding flexmux)

>Thanks.
>
>
>Deckard.
>
>  
>

Can you upload 1+  sample[s] in ftp://www.mplayerhq.hu/MPlayer/incoming, 
and post the filename[s] please?

    Nico