search for: keyframe

...ctshow 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 video is at 5 fps. Although I can't find explicit documentation I presume that the Keyframe Frequency is actually the keyframe interval measured in frames (what h.264 would call GOP.) I need frequent keyframes for input to...

...lient connects we send out the theora header pages followed by the actual live stream pages. The problem is that the first ogg data page does not have the right page number (2), which causes libogg to not want to decode the first _packet_ of that page. Since that first packet happens to contain the keyframe of the theora stream, most players (Mplayer) don't properly show the first frames until a new keyframe is received. This is not nice. In comming up with a solution we can see following scenarios: 1) libogg does not refuse to decode the first packet, just warn. This requires changing libogg be...

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...

Hi, I am continuing to try to debug my ogg/theora decoder. The issue seems to be that not enough packets are being pulled from the bitstream, here is some sample output from my player with some debugging comments put in: (playback began at first frame, this is from the middle of the clip) get page at 1765027 got packet frame++, skip is 0 frame decoded page processed, kframe=414 : offs=442 get

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

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 rised during implementation: - How do I extract the keyframe number? Is shifting the granule position by "...

...info.fps_numerator = 10; info.fps_denominator = 1; My understanding is that this is the framerate, and that the parameters above means 10 frames per second, Is that right? info.aspect_denominator = 0; info.aspect_numerator = 0; Here I use the default, and hope that is OK. info.keyframe_granule_shift = 10; I'm uncertain on what the intention of the parameter is. It seems like it is the frequency keyframes are sent in, so the parameter above would mean that every 10th frame is a keyframe, but I'm not sure that is right, and would like this parameter to be explained, as...

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 for wavelet-encoded key...

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 lack of a painfully explicit spec has led to the t...

...have difficulties understanding some particular point of the process, and the actual theora svn code source is very difficult to corelate with the theora documentation (not same vocabulary, names of variables, way of decoding...)... My question is: has anyone done any simple decoder, for a single keyframe, in any structured langage I could reuse the code (c, c++, php, python, perl, java, anything ?) Thank you very much in advance... Nicolas _________________________________________________________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists...

> From: Jay Sprenkle [mailto:cupycake_jay@yahoo.com] > I thought > you had to back up to the previous complete frame, > then apply the differences in the following frames > to generate a new complete frame where the splice > was to happen. Are you going to handle editing to > arbitrary frames? I believe you have to do something > analogous in theora/ogg. yup. > ---

Hi, I'am using the Xiph Theora Encoder directshow Filter in a csharp application. It works fine but I would like to modify the configuration, like the quality settings. I would like to know if there is a possibility to configure it programmatically without using the propertyPage dialog. Thanks a lot for your help Mathieu -------------- next part -------------- An HTML attachment was

(I think Timothy intended for this to go to the list; my apologies if it wasn't.) -------- Original Message -------- Subject: Re: [Theora-dev] Force keyframe creation Date: Sat, 06 Aug 2005 00:06:32 -0400 From: Timothy B. Terriberry <tterribe@vt.edu> To: David Barrett <dbarrett@quinthar.com> References: <42F4186C.1050605@quinthar.com> David Barrett wrote: > Is there any way to force the creation of a keyframe when encoding? > &...

...treams. 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: thusnelda-14589-keyframe-only.patch Type: text/x-patch Size: 437 bytes Desc: not available Url : http://lists.xiph.org/pipermail/theora-dev/attachments/20080315/ce430cc9/thusnelda-14589-keyframe-only.bin

I'm new to the list so please excuse me if this has already been rehashed before. There seems to be something very odd about how the PP_INSTANCE::PrevFragments array is handled during keyframes. I'm not a video codec expert so I'm not entirely sure what the reason for keeping a history of blocks updated in the last few previous interframes and adding them to the blocks to be updated in the current interframe is, but I'm sure there's a good one (perhaps it's to fur...

...ces; [ComVisible(true), ComImport, Guid("4F063B3A-B397-4c22-AFF4-2F8DB96D292A"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface ITheoraEncodeSettings { [PreserveSig] bool canModifySettings(); [PreserveSig] ulong targetBitrate(); [PreserveSig] ulong keyFrameDataBitrate(); [PreserveSig] byte quality(); [PreserveSig] long sharpness(); [PreserveSig] long noiseSensitivity(); [PreserveSig] ulong keyframeFreq(); [PreserveSig] bool isFixedKeyframeInterval(); [PreserveSig] bool allowDroppedFrames(); [PreserveSig] bool isUsingQuality...

...edia@gmail.com> Date: Aug 19, 2007 10:13 AM Subject: [show-in-a-box] Re: Ogg To: show-in-a-box@googlegroups.com A question I have if you would know. OGG from what I know comes from an early version of the Flash codec that ON2 is building. The FLV file structure does not have frames, but only keyframes, to optimize for streaming -- that's why FLVs can't be edited in Premiere or Final Cut. Does OGG have a similar limitation of not being fame editable and only having keyframes? -- Enric

Hello, i am member of red5 project. I am studying ways to integrate your codec into red5 and in a near future inside Flash Player. I want to figure some things about Theora codec. -> Is theora proper for live streams (i.e live transcondig webcam)? What is latency for encoding process? -> Is the format tolerant to lost frames? Thanks for the moment.

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/

...e buffer that was output for the last frame that had a non-zero MotionScore. This is obviously incorrect behavior. I've just moved the UpdateFrame() out of the (MotionScore > 0) conditional block. I've also included my change that prevents the encoder from spending WAY to many bits on keyframes. This helps prevent the artifact where the video suddenly gets very clear when keyframes occur but gets progressively blurry for interframes. This change helps minimize some of the drastic Q changes that cause this artifact. Aaron Index: encoder_toplevel.c ======================================...