OK... i figured out the deal with the granule pos increasing... that's to do
with the keyframe thingy-bob in theora, but i'm still unsure about the
correct way to indicate no packets ending on this page.
Thanks
Zen.
----- Original Message -----
From: illiminable
To: theora-dev@xiph.org
Sent: Thursday, April 15, 2004 8:12 PM
Subject: Granule pos bug ?
<p>After trying to find out what to do when no packets complete on a
page... i
reread the ogg spec and found this...
"A special value of -1 (in two's complement) indicates that no packets
finish on this page."
So i searched through a few files and it appears that the muxer doesn't do
this... has this been depracated ? In all cases i can find that this happens
the page has the same granule pos as the previous page.
Is this a bug in the encoder or muxer or is the spec wrong ?
Also when looking more closely the granule pos appears to get out of whack
at each point where this happens... with the granule pos increasing by a
large amount. An example....
Ver No : 0
Head Flags : 1
Granule Pos : 63
Serial No : 1414378159
Seq No : 11
Checksum : 1172679884
Num Segs : 20
------------------------
Head Size : 47
Data Size : 4321
Page Size : 4368
Num Packets : 7
------ Packet 0 (266 bytes) -------
------ Packet 1 (553 bytes) -------
------ Packet 2 (509 bytes) -------
------ Packet 3 (464 bytes) -------
------ Packet 4 (535 bytes) -------
------ Packet 5 (464 bytes) -------
------ Packet 6 (1530 bytes) ------- ** INCOMPLETE **
============================================================================Ver
No : 0
Head Flags : 1
Granule Pos : 63
Serial No : 1414378159
Seq No : 12
Checksum : 686927226
Num Segs : 17
------------------------
Head Size : 44
Data Size : 4335
Page Size : 4379
Num Packets : 1
------ Packet 0 (4335 bytes) ------- ** INCOMPLETE **
============================================================================Ver
No : 0
Head Flags : 1
Granule Pos : 4104
Serial No : 1414378159
Seq No : 13
Checksum : 2446388238
Num Segs : 22
------------------------
Head Size : 49
Data Size : 4297
Page Size : 4346
Num Packets : 10
============================================================================............
============================================================================Ver
No : 0
Head Flags : 5
Granule Pos : 81225
Serial No : 1414378159
Seq No : 330
Checksum : 2404328773
Num Segs : 16
------------------------
Head Size : 43
Data Size : 2311
Page Size : 2354
Num Packets : 10
<p><p>Notice on the second shown page (seq no 12) the granule pos is
the same as
the page before instead of -1... also notice on the next page (no 13) the
granule pos is now 4104... the video is only 40 seconds long @ 25fps
~1000frames.
And by the last page of the video bitstream the granule pos is way up to
81225.
Anyone have any idea what could have caused this ? And what is the correct
way to indicate no packets end on a page ? Is it -1 or the same as the
previous page...
Cheers,
Zen.
<p>--- >8 ----
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