similar to: Granule pos bug ?

Hi, I've seen several implementations of Ogg demuxing that use a zero granulepos to detect headers. However, I do not recall seeing this in the Ogg docs - is this an abuse that happens to work because Vorbis is timed by end granule, or is it a proper way to check ? Thanks

I have a technical question about the vorbis granule position, but I would like to put the question into context. When a ogg vorbis stream is ripped using wget, fetch, or streamripper under Linux or FreeBSD, the resulting file has problems both with granule position and with a missing EOS. I think I can figure out how to add an EOS, but is there a way to determine the granule position in a stream

OK... i've come across a problem trying to get the granule pos of the start of the page... it's not so crucial with single stream ogg files... but now that i have theora+vorbis in a file, i'm finding that when i seek to a position, i have no way to determine the relative offsets of the different streams at the new seek point and hence the av is out of sync. So given a page, is it

Hi, If this is true: "Granule Position Information in Ogg Header is a hint for the decoder and gives some timing and position information." So say if granule position is 10000, it means that 10000 PCM samples are encoded in this page approximately. If this is true we can neglect this information, it will not effect the decoding right(but might effect for streaming)? Ravi

Hi! I don't find any detailed information about this in the specification, so I try a question here. If two plain, unmultiplexed Ogg/Vorbis-files are chained into one file, you end up with an Ogg-file with two logical Vorbis streams. When playing this file, would it be correct for a decoder to synchronize the two streams according to the granule position of the Ogg pages (playing them

Hi, What are the two granule rates in a fishead packet supposed to be for ? Since each of the streams has a corresponding fisbone packet with its own granulerate in it, and they can be all different, wha does the presentationtime num/den means ? Also for hte basetime num/den, since the UTC time which is also present in fishead seems to be a textual representation rather than a linear count ?

> No particular answers, but I can at least point out that the way > things were designed for CMML was to work with the existing Ogg > seeking algorithm. The idea is that a generic seeking routine can work > on any Ogg file, as long as it knows the granulepos->time mapping for > the logical bitstreams in the file. That's why all the > timestamp-related info is crammed into

> The advantage of storing this in the granulepos field itself, like > theora and CMML do, is that the seek code may already understand how > to handle the back pointer. Right now everything assumes the mapping > is from 'initialized decoder' + 'granulepos from page header' => > timestamp, or in the case of theora and CMML => 'timestamp' + 'last

Listening to the meeting on granule pos tonight/today it became clear that the issues everyone is concerned with for the most part don't affect my implementations and the issues i have pretty much don't affect anyone else... and in the cases where they overlap, the reasoning seems to be different. And since everyone else has had a lot more time to consider all these issues and i'm

Hi, do you still think you need all this, if you are allowed to have equal granulepos on subsequent pages? Conrad. On 18/02/2008, ogg.k.ogg.k@googlemail.com <ogg.k.ogg.k@googlemail.com> wrote: > Hi, > > I've now got another way of encoding granule (oh, not *again*, I hear > you cry). I believe it's an improvement over the existing "generic" > method, so

Hi, I have a question about seeking. In fact, it's more or less a kind of rambling and thinking aloud, circling around a question. I've been wondering how to deal with seeking in a stream, and what to do when seeking in the middle of a set of active events (eg, when several bits of text are supposed to be shown, but you seek after the time when they are first shown, and before the time

Hello all, there is an ambiguity within the Vorbis specification regarding the granule position of the Ogg encapsulation. I'm referring to section "A.2. Encapsulation" of the Vorbis I specification, as found here: https://xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-132000A.2 The specification both says > The granule position of these first pages containing only headers > is

> It is more complex, because the granulepos is available at the page > level. Ah. Good point, I always forget about the partial page problem :( I conveniently flush pages after each data packet in my case (due to unknown/arbitrary latency), so I tend to forget easily about those. > We've generally designed the seeking algorithm so it can be > implemented without looking inside

I've got a few theora vids here... and looking at the headers it seems to me they say they play at 2 frames per second... but watching them they appear to to play at a faster rate. Theres also some that say they lpay at 1 fps. Am i missing something here ? I'm getting the info from here.... http://wiki.xiph.org/TheoraSpec Is this header structure still valid ? Heres a dump of the BOS

Hi, sorry, there is a bug in the CMML spec and wiki page ... I discussed this with Silvia earlier this week but haven't gotten around to correcting it yet. CMML granulepos is much like theora's; the previous granule is stored in the higher bits, and the delta since then is stored in the lower bits. The current timestamp is the sum of the two. This is the behavior of the implementations

Just playing around with my new flac code, and did some tests with stuff from the reference tools, and i noticed that one of the fields in the first header is wrong. (The number of headers field is 1 less than it should be) The spec doc says... " A two-byte, big-endian binary number signifying the number of header (non-audio) packets, including this one. " Here's a partial dump

Thought I'd pass this along for Theora users on the Windowzz platform. The latest alpha build of the ffdshow filter (20041003) on Sourceforge http://sourceforge.net/projects/ffdshow/ Seems to have had theora, broken since the June/July unofficial builds, fixed. This build also connects nicely to Zen's Ogg splitter and also decodes Helix Producer encoded Ogg's well. The encoder side

I'm hoping this is a new proposal, and not a rehash of something that's already been discussed and shot down. Without logs of the recent IRC discussion there's no way for me to know without asking. When I suggested it in #theora earlier derf_ or AndrewBachmann said that it had already been discussed, so I'm under the belief that this is a new idea. <p>Ok so we've

David Flynn has proposed a new Ogg Dirac mapping. The draft is here: http://davidf.woaf.net/dirac-mapping-ogg.pdf This is a much bigger break from other codecs than my draft (at http://wiki.xiph.org/index.php/OggDirac). We talked a bit about it on IRC today. Below is my summary; hopefully David can correct anything I got wrong or misleading. Comments? There are two main differences

Dear all I'm aware that there have been several discussions about the seeking issue and I'm sorry to bring this up again. To solve the problem with Inter-Frame garbage, a seek to the previous keyframe has to be made. The keyframe number should be extracted from the granulepos of the frame where we want to seek to. I hope I understood the theory - unfortunately a few questions have