similar to: ogg and keyframes

Here is a fix that prevents the encoder from spending too many bits on keyframes. The main problem is that the old code computes the target keyframe bitrate incorrectly. This causes the code that computes the Q for the frame to think that it has tons of bits to spend. It selects a high Q value for the keyframe. Since so many bits were spend on the keyframe the the inter-frames have to use a much

Hi all, First of all a big thank you for your work. I would like to know what is (could be) the best (optimal in a psnr and/or subjectivity sense) maximum distance between keyframes or is theora using a good heuristic change scene detection mecanism? Does it really matter to theora as with mpeg4 part2/10? Thank you and keep up the good work -- Josh

Hi people, Next issue at hand here is after I have done a seek in a theora file. At this point, I have to reinitialize the decoder so the viewing can continue. Again, I have code that works most of the time, but, well... Just after the last file position seek, this code is run: while ((result = ogg_sync_pageout(&sync, &page)) == 0) bufferData(); while

Monty, Derf and I were discussing some theora bitstream improvements. He was curious about the spare bits in the keyframe header. There's a keyframe type bit which is always DCT_KEY_FRAME aka '0' and two spare bits. You took out a lot of similar extra bits in the VP3 code. Do you remember anything about the motivation for leaving this one in? Given the constant, were there plans

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

Hi everyone! I'm currently trying to use the theora decoder on PPC. Everything is working perfect now, but I have a problem: I need to skip the decoding of some frames (drop frames) when the device is not powerful enough to decode them all in real time (which in PPC is a frequent issue). Right now, I'm skipping the call to theora_decode_YUVout and the yuv to rgb procedure. That gives me

Hi all, I'm actually learning how to use ogg, theora and vorbis. My idea is to create a small program running, that is able to concatenate ogg video+audio files. However I have some small questions. Here I will start with the first one: I read the following for seeking in ogg for a theora key-frame: ---- snipp (http://www.xiph.org/ogg/doc/ogg-multiplex.html) ---- [...]The third point

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 have almost finished integration of Theora into our videoconferencing program. Since a videoconferencing program is realtime, it is UDP-based and wraps the Theora stream in RTP (More on that later). The problem here is that most examples I could find, wraps the theora stream in ogg, and used over tcp or files. I send over UDP and clients need to be able to start in the middle of the stream.

Hello everybody ! I am working on a php class to enable, on the server-side, to extract useful data from Ogg theora videos. http://opensource.grisambre.net/ogg . I need to have it extract a thumbnail picture from a video (much like dailymotion or youtube). Right now, I am doing it using the ffmpeg-php extension (for picture extraction only), but the problem is that this module is available on

I am using the directshow Theora encoder to compress a live video stream. A dump of the encoder settings is given below. The starred settings have been explicitly configured and the others are defaulted or derived values. These settings produce an even, dark (almost black) recorded result as does any recording with Keyframe Freq <= 32. Keyframe Freq >32 works perfectly. The incoming

Here is a patch that fixes distortions that appear during scenes with no motion. Tbe problem was that UpdateFrame() was not being called when a MotionScore of 0 was computed. Since UpdateFrame() was not called the buffer returned by theora_encode_packetout() would be the same buffer that was output for the last frame that had a non-zero MotionScore. This is obviously incorrect behavior. I've

Hi all, Attached is a trivial patch that speeds up encoding for key frame only streams. It skips the motion vector search which is not needed when there are never going to be any delta frames. It was made against thusnelda SVN revision 14589. Tested on Fedora 8 x64_64. -Phil -------------- next part -------------- A non-text attachment was scrubbed... Name:

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

Updated version of video preview covering frame writing every 3 keyframe and a xsl typo. Best regards :) kysucix -- Make things as simple as possible, but no simpler. - Albert Einstein

Hi. Here it is my patch to put a video preview of a theora stream in status.xsl. I just added a: <video-preview>1</video-preview> parameters in icecast.xml.in that control the previewing function. It encodes a png in $webroot/$mountname.tmp and then move it to $webroot/$mountname.png As for now it saves a frame every theora keyframe, which is probably too heavy for the server but

Is anyone working on liboggplay, and if so, is there any plan to support keyframe-based seeking? I found this, but seems to me that the feature ought to be part of liboggplay: http://pearce.org.nz/2009/05/video-seeking-improvements.html Is there a more appropriate list to post to regarding liboggplay? Shayne Wissler -------------- next part -------------- An HTML attachment was scrubbed...

Howdy, tl;dr: Nothing new or interesting to non-developers Attached is a newer Icecast WebM support patch for Icecast SVN, there is simply aesthetic changes. Whitespace has been altered to match Icecast project style, some functions have been renamed and moved around. Some discussion. The format_ebml.c file lines 0-296 operates much the same as the format_ogg.c file does. It uses a parsing

Howdy, tl;dr: Nothing new or interesting to non-developers Attached is a newer Icecast WebM support patch for Icecast SVN, there is simply aesthetic changes. Whitespace has been altered to match Icecast project style, some functions have been renamed and moved around. Some discussion. The format_ebml.c file lines 0-296 operates much the same as the format_ogg.c file does. It uses a parsing

Hello, Does anyone know the answer to this question below? (Note... they're calling the Theora codec "Ogg" below. I know technically it's not correct... but that's what some are calling it.) ---------- Forwarded message ---------- From: Enric <enric.media@gmail.com> Date: Aug 19, 2007 10:13 AM Subject: [show-in-a-box] Re: Ogg To: show-in-a-box@googlegroups.com A