similar to: Questions about encoder parameters.

Hi There, i want to stream some pictures out of my application using the Theora codec. I can stream to a socket or a file. The current work based on the png2theora example. Something while enconding went wrong: I can see the whole video in VLC, but the complete duration of the file will not be displayed. If i play the video in Firefox, the first 2 seconds will not be played. I think the

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

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 Is there a way to estimate the number of bytes per second from the information passed in the th_info-struct to the Theora encoder's th_encode_alloc()? I'm trying to be able to give users a rough estimate of the file size needed to encode with the setting provided to th_info-struct (frame width/height, fps_numerator/fps_denominator, target_bitrate and quality). -- Bjoern

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

Hello everyone, I'm currently developing an adaptive videoconferencing application based on Ekiga which uses TFRC as a congestion control mechanism to adapt the video encoding rate according to the quality of the network experienced. My goal was to use the open-source Theora codec for video transmission. Unfortunately, it seemed that Theora 1.0 did not properly implement any correct CBR mode.

On 15-Feb-08, at 6:44 AM, ogg.k.ogg.k@googlemail.com wrote: > Well, it doesn't quite work because the second part of the gpos is > an offset, > rather than absolute, and the precision we shed on one, we need to > recover > on the other one, to keep the ability to timestamp events at the > correct > granularity. It would have worked if the second part was absolute

I am trying to write a sample app that uses Theora for encoding/decoding a network video stream. Unfortunately, I keep running into this error: Run-Time Check Failure #3 - The variable 'MVect' is being used without being defined. It always happens on decryption, line 467 in decode.c. The issue is that CodingMethod is equal to 5 (CODE_GOLDENFRAME), which doesn't initialize the

Hi, Attached is my patch to add theora encoding to ffmpeg's libavcodec (by using libtheora). I am requesting help to fix the bug I mention below and am seeking general comments before I submit the patch properly. Files encoded using this encoder have a problem playing in VLC. The files will not play unless "Drop late frames" has been unticked in the advanced video settings.

Hi Sahana I must admit I'm not an expert in Theora. But the error message "Could not set keyframe interval to 64" might indicate that an attempt to set the keyframe frequency failed. Have a look at the keyframe_granule_shift attribute in the th_info struct. It says: The maximum distance between key frames is 1<<keyframe_granule_shift. So I could imagine that the error might

The definition of granule position for an OggDirac elementary stream isn't the same as theora. Index: tools/oggz_tools.c =================================================================== --- tools/oggz_tools.c (revision 3759) +++ tools/oggz_tools.c (working copy) @@ -454,7 +454,15 @@ iframe = granulepos >> granuleshift; pframe = granulepos - (iframe << granuleshift);

??????? I've rewritten my theora player using liboggz. I've stumbled upon a few issues though. First of all liboggz exposes oggz_read and oggz_run, but how can i read only sound data, or only video data using liboggz, say something like this: oggz_read_sound(1024), oggz_read_video(1024). ? ? ? ?? Second of all i tried using liboggz's seek function. Immediately after the seek i get some

For last few days I was trying to learn ffmpeg and libtheora API. In the process, I have modified ffmpeg2theora code to include support for start time and end time. ffmpeg2theora -s 60 -e 130 file.avi will produce file.ogg which will be from 60th to 130th second of input file (something like -ss and -endpos in mencoder). This is a useful feature for someone who wants to cut a part of video

Hi all. I post a small app I made that create 2 clips using a V4L device. I would like to get every tips you think it's useful... Some notes: - I make 2 clips because in our project we create series of clips and it's important to check that the all the resources ( memory, descriptors, etc. ) are freed correctly and to reuse all the resources that can be reused - the clips are not well

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

below is an rfc-style bitmap of the initial theora header. I've checked it against the spec and the code in libtheora; please double check :) I'm posting it here for those implementing demux stages (which necessarily don't use libtheora), and hence offering it for the spec. A typical demux stage just needs to pick out the FRN, FRD and KFGSHIFT fields, without going through the whole

Hi all. In my test application I saw that the encoding process with Theora is too CPU expensive ( compared to FFmpeg - MP4 ) ... Perhaps I'm using wrong parameters: ti.fps_numerator = fps * 11 + 1; // var framerate ti.fps_denominator = 11; ti.aspect_numerator = 1; ti.aspect_denominator = 1; ti.colorspace = OC_CS_ITU_REC_470BG; //

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

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.