similar to: A/V sync in Theora

I tried to encode some video from a DVD with encoder_example and ffmpeg2theora, and it looked great, except that with both encoders the A/V sync would drift noticeably after about 10 minutes, and by the end of a two hour movie it would be a couple seconds off. So instead of just whining about this and waiting for someone else to fix it, I decided to try to learn about what's causing the

Hi all, > One problem I see with your proposed implementation is that it does not > specify how audio and video would be synchronized, since there are no > absolute time stamps for the video frames. So it is difficult to account > for > audio latency on different systems, much like when you play an AVI file. > Ideally it would be wonderful to have timestamps that could be used

Okay, thanks to some stubbornness on my part and helpfulness on the part of people on this mailing list, I got the Ogg Theora alpha compiled up and installed and running. Yesterday, I went to the Prelinger archives (the public-domain video archive at www.archive.com) to find a high-quality original to re-encode as a test. The encoder worked just fine, and playback as well, and I thought I'd

hi guys, first of all, i'd like to ask if there any crossplatform software/service ( gui is also better, an online application like firefogg is great, or at least a command line tools for any platform) to combine theora videos, other than oggcat... i am doing some art projects that people should be able to remix featured theora videos and i find oggcat very usefull in theory but not in

Hi I'm trying to store video I encode to a file using Theora and Ogg. The video I record is from my webcam and although the framerate is set to 30 fps I rarely get more then 28-29 fps. Since Theora is fed with a framerate which isn't precise the time of each frame when I play it in VLC doesn't match the exact time of when the frame occurred. So basically I wonder how can I sync a

Folks have noticed that the documentation is semi-silent about how to properly encode the granule position and interleave synchronization of keyframe-based video. The primary reasons for this: a) we at Xiph hadn't had to do it yet b) there are several easy possibilities, and the longer we had to think about it before mandating One True Spec, the better that spec would likely be. The

2008/11/21 David Flynn <davidf+nntp at woaf.net>: > On 2008-11-21, Conrad Parker <conrad at metadecks.org> wrote: >> 2008/11/15 David Flynn <davidf+nntp at woaf.net>: >>> On 2008-11-14, Conrad Parker <conrad at metadecks.org> wrote: >>>> It seems oggz chop, merge and sort will need some attention to deal >>>> with the Dirac

Question: is it permissible to put more than one frame packet into a page? At 30 fps, Ogg page overhead is on the order of 8 - 10 kbits/sec. At low datarates, this is going to be unacceptable. If I shove a few frames into a page, how does this affect the granulepos stuff? ___ Dan Miller (++,) Founder, On2 Technologies <p>--- >8 ---- List archives: http://www.xiph.org/archives/

I found out about vp3 from the new winamp and coincidentally i also happen to be trying to find a suitable solution to broadband streaming. I have used flaskmpeg to create a 17mb .avi file from an 82mb Mpeg 1 file and it looks great it took about twenty minutes to encode. It runs for eight minutes and the audio is also fantastic using the lame encoder. However when I try to do the same in

Hello, > (1) Split the content into chain segments > (2) extract the first and last data packet from each segment, for all tracks > (3) recover / calculate the granulepos values for the first and last data packets (*) > (4) convert the granulepos values from the first and last data packets into time values > (5) take the largest difference between start and end time as the total

Has anyone noticed this? I have a video made with Final Cut Pro, which I convert to .mov via Compressor. This .mov file plays back fine in Quicktime. But when I then use ffmpeg2theora to convert to ogv, the video seems to play back too fast compared to the audio (I'm using VLC 1.0.2, the latest I believe, to play back the ogv file, and I also have an app that uses the recently

2008/11/15 David Flynn <davidf+nntp at woaf.net>: > On 2008-11-14, Conrad Parker <conrad at metadecks.org> wrote: >> It seems oggz chop, merge and sort will need some attention to deal >> with the Dirac granulepos and dependency ordering, so let's leave them >> for the next release. > > ok. -- may be worth having them 'warn' if they are operating

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

As I understand it the current plan is to make it possible to losslessly transcode VP3 video to Theora video. In my experience, one of the "features" of VP3 is it drops frames in the event that there is little/no movement in a frame, or if "drop frames" is enabled, to drop frames if the data rate is getting too high. I understand that the way that VP3 does this in

Taking a look ahead at your QT (OSX version) work, you have Theora Encoding and Decoding on the list. This could be very beneficial as many times the only way to get a constant frame-rate out of QT is to export (and for DV video recorded in QT, this can be a large issue). Another major issue is that the video coming from DV (at least the sources I have used) is almost always

When I converted two files with ffmpeg2theora their duration changed shorter - they seem to play back with accelerated speed. When I play one of them with VLC, the video stops at 99 seconds but audio continues until 170 seconds. The other file is 120 seconds long but it is played back in 80 seconds. Here is ffmpeg2theora output: $ ffmpeg2theora --optimize --inputfps 25 -F 25 2002-05-23\ Juho\

Hello, I'm just totally confused. In my theora streams encoded using ffmpeg2theora (but also when using my own encoder) I have packets with a granulepos of -1 so I can't identify the packet during a seeking operation correctly. I can also see those strange value when I just print the packet granulepos before sending it to the Theora decoder. I know why there are PAGES with granularpos of

2008/10/29 Romain Beauxis <toots at rastageeks.org>: > > I am currently implementing theora for our application. > In our model for generating ogg streams, we may want to stop > a stream while not providing a new YUV data buffer for encoding. > > Current API doesn't allow such thing, since the eos flag is set by the > packetout function only when the last_p parameter

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello, I just want to know whether it would be possible to play ogg-theora videos on my favourite Handheld, the GP2X. For those of you who don't know the GP2X yet there's much information about it on Wikpedia or on http://wiki.gp2x.org/wiki/Hardware_Documentation . To make it short, its an ARM-based Handheld which is able to play Xvid and DivX

Hi all I'm currently writing a decoder for Ogg Theora videos. Since I'd like to show the progress of the video, I need to know how to read the current (with granulepos?) and total number of frames from the Theora header. I didn't find an appropriate field in the header specifications for the total number. Thanks for helping me out with this. Regards, Stefan