[ogg-dev] ogg dirac granulepos in oggz tools

[Conrad Parker]

2008/11/26 David Flynn <davidf+nntp at woaf.net>:
>>>> http://trac.annodex.net/changeset/3801
>>>
>>> I'll test this shortly.
>
> Ok, i've tested muxing some audio and video together and that works fine.
> woo.

great, thanks :-)

So the last remaining tool to check is oggz-chop. I at first assumed it
would not work with Dirac's granulepos, but it seems to do something
vaguely useful:

conrad at chichai:~/share/oggz-chop$ oggz chop -s 7 -e 11 -o
sage-7-11.ogv ../dirac/sage-640x360.ogg
conrad at chichai:~/share/oggz-chop$ oggz dump sage-7-11.ogv |grep
serialno | head -n 20
00:00:00.000: serialno 1762443388, granulepos 0, packetno 0 *** bos: 64 bytes
00:00:00.000: serialno 1763535876, granulepos
(pt:0,dt:0,dist:0,delay:0), packetno 0 *** bos: 39 bytes
00:00:00.000: serialno 0719746932, granulepos 0, packetno 0 *** bos: 30 bytes
00:00:00.000: serialno 0719746932, calc. gpos 0, packetno 1: 75 bytes
00:00:00.000: serialno 0719746932, granulepos 0, packetno 2: 3.742 kB
00:00:00.000: serialno 1762443388, granulepos 0, packetno 1: 80 bytes
00:00:00.000: serialno 1762443388, granulepos 0, packetno 2: 81 bytes
00:00:00.000: serialno 1762443388, granulepos 0, packetno 3 *** eos: 0 bytes
00:00:06.923: serialno 1763535876, granulepos
(pt:334,dt:332,dist:51,delay:2), packetno 2: 1.685 kB
00:00:06.965: serialno 1763535876, granulepos
(pt:344,dt:334,dist:52,delay:10), packetno 3: 16.928 kB
00:00:07.007: serialno 1763535876, granulepos
(pt:338,dt:336,dist:53,delay:2), packetno 4: 1.529 kB
00:00:07.048: serialno 1763535876, granulepos
(pt:340,dt:338,dist:54,delay:2), packetno 5: 1.761 kB
00:00:07.090: serialno 1763535876, granulepos
(pt:342,dt:340,dist:55,delay:2), packetno 6: 1.576 kB
00:00:06.857: serialno 0719746932, calc. gpos 329152, packetno 4: 1 byte
00:00:06.878: serialno 0719746932, calc. gpos 330176, packetno 5: 1 byte
00:00:06.900: serialno 0719746932, calc. gpos 331200, packetno 6: 1 byte
00:00:06.921: serialno 0719746932, calc. gpos 332224, packetno 7: 1 byte
00:00:06.942: serialno 0719746932, calc. gpos 333248, packetno 8: 1 byte
00:00:06.954: serialno 0719746932, calc. gpos 333824, packetno 9: 1 byte
00:00:06.957: serialno 0719746932, calc. gpos 333952, packetno 10: 45 bytes

However I don't know if this output is correct. What it is supposed to do
is create a file containing all packets for display between 7 and 11 seconds,
and to include all packets required to decode those, ie. all reference
frames that are required by packets from 7s onwards.

The original file included two more Dirac packets immediately prior to
those included
in the chopped output, but I don't know how to tell if these are
required reference
frames for those from 7s (or from 6.965s) onwards:

conrad at chichai:~/share/oggz-chop$ oggz dump ../dirac/sage-640x360.ogg
|grep serialno
...
00:00:06.814: serialno 0719746932, calc. gpos 327104, packetno 406: 1 byte
00:00:06.836: serialno 0719746932, granulepos 328128, packetno 407: 1 byte
00:00:06.840: serialno 1763535876, granulepos
(pt:330,dt:328,dist:49,delay:2), packetno 168: 1.603 kB
00:00:06.881: serialno 1763535876, granulepos
(pt:332,dt:330,dist:50,delay:2), packetno 169: 1.683 kB
00:00:06.923: serialno 1763535876, granulepos
(pt:334,dt:332,dist:51,delay:2), packetno 170: 1.685 kB
00:00:06.965: serialno 1763535876, granulepos
(pt:344,dt:334,dist:52,delay:10), packetno 171: 16.928 kB
00:00:07.007: serialno 1763535876, granulepos
(pt:338,dt:336,dist:53,delay:2), packetno 172: 1.529 kB
00:00:07.048: serialno 1763535876, granulepos
(pt:340,dt:338,dist:54,delay:2), packetno 173: 1.761 kB
00:00:07.090: serialno 1763535876, granulepos
(pt:342,dt:340,dist:55,delay:2), packetno 174: 1.576 kB
00:00:06.857: serialno 0719746932, calc. gpos 329152, packetno 408: 1 byte
00:00:06.878: serialno 0719746932, calc. gpos 330176, packetno 409: 1 byte
...

So:
 - is the current output correct?
 - if not, how should the packets that a given packet depends on be determined,
   ie. how to determine reference frames? Is it possible to do so using only the
   granulepos encoding?

Conrad.