similar to: question from beginner (YCbCr to RGB)

I've spent the weekend or so trying to get my head around Theora and I'm just not having any luck. First of all, I really don't have any interest in immersing myself in video encoding--I just have one simple thing I'd like to do--so I haven't spent any time reading about the theory or specs or anything like that. I'm attempting to write a "render-to-theora"

Hi everybody, me again. I'm trying to write my own VFW-like dll... It doesn't need to do much. 1.) compress a single frame and give it back to the host application 2.) host applications sends the frame 3.) client application receives frame 4.) client application tells the dll to decompress the data So if I try to do this, something is going wrong... Perhaps someone could have a look at my

Hi all. I'm Mat & I'm new :) I'm testing libtheora + libogg perhaps for a commercial product. I started watching encoder_example.c ... I simplified it for testing it easier. It seems ok to me but I have no experience with theora so I would like to know if my code is correct. I tried to debug it with Valgrind and I found 4 possible memory leaks... but I think they can be

I posted this the other day... but it didn't get delivered... ------------------------------------------------------------------- I'm getting stuck into a theora decoder for directshow... i was just wondering if someone could give me some info. What output format does theora use ? http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/YUVFormats.asp

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

Just trying to debug my theora encoder... just wondering if someone could give me some insight on a few thigns... In the yuv_buffer i'm sending in... i am just setting y_stride = y_width = videoWidth uv_stride = videoWidth/2 y_height = videoHeight uv_height = videoHeight/2 Making the y buffer (width*height) and each of u and v (width*height/4) Am i correct in doing this ? I knwo stride

Hi there, is there any document giving a high-level overview of how to use "libtheora"? As it stands, I'm scrounging through headers and example code, and doing a whole lot of guessing. In the meantime, could you either confirm or deny the following guesses? 1) Before compressing with Theora, I must unpack my YUY2 data into three separate arrays (Y, U, and V respectively), and

hi all, i'm trying to code a tool to get some images from a ogg/theora file .... so basically i need to get a frame and convert to rgb ... and here is my question (sorry, i'm newbe here) ... how to convert a yuv_buffer to a rgb matrix ? i tryied diferent ways but my mistakes are bassically cause i don't understant how yuv_buffer structure works ... anybody can help? thanks a lot.

I'd previously been working on the assumption that the frame_height was the height of the inner picture region... and height was the height of the outer frame. Then upon readnig the spec... where it calls the outer part the frame and the inner part the picture region... i assumed i'd made a mistake and that frame_width is actually >= width in the theorainfo structure... ie

Hi, I coded some routines for YCbCr <-> RGB conversion, both using floating point numbers and using integer arithmetics, code is attached. Let's say I want to convert from RGB to YCbCr and back. First the integer arithmetics: In [1]: from colors import * In [2]: a = [255, 0, 255] In [3]: RGB2YCbCr(a) Out[3]: (107, 202, 222) In [4]: YCbCr2RGB(RGB2YCbCr(a)) Out[4]: array([255, 1,

Hi, is there any place where the possible values for the strides in the yuv_buffer structure is specified? or just in the source code? ;) I could compress a video with, lets say, yuvbuf.y_stride = yuvbuf.y_width, so the yuvbuf.y[0] really started in the start of the y channel data. I watched the video in several players, and everythings' ok. But, when programming the decompress process, the

Mike Melanson: I want to store RGB values instead of YUV. I don't understand the theoretical and practical implications of this and that's why I'm asking about it. I would like to know whether it cannot work and why. I'm targeting a minimum Pentium 4 Celeron, 256MB RAM. Video resolution are about 200 X 200 pixels with a maximum of 2 playing simultaneously as the game is playing

Hello, I'm new to this list, and pretty much also to the codec universe. In a computer game I'm working on, there is an 3D TV-screen onto which I project the frames of a movie. The movie is of course stored as theora, no audio as it's not needed yet. I have it working so far, extracting a frame and uploading it to the graphics card when the scene is drawn. The example file

Hello all, I'd like to convert the theora yuv_buffer to RGB that I can render onto a texture. Googling around, there are a tone of different formulae to do so. There is this (with lots of corrections and amendments further down the page): http://www.fourcc.org/fccyvrgb.php <http://www.fourcc.org/fccyvrgb.php> and there is the MSDN stuff that says you need to convert 4:2:0 and

Hello, Just a very quick message to let you know that I have definitely switched to YCbCr color space as YCbCr is better, more precision.I have updated my demo page: http://nhwcodec.blogspot.com/ . Any comment on this new version from the Xiph Community would be very appreciated, as I am developing alone (it really took some time to switch to YCbCr...).Also (as it was said), I am not totally

hi all I guess that *Theora* will convert the input color space (RGB or CMYK or any) into YUV before it process and encode. (that means theora can operate on several color space, but it get convert into YUV before process) Is that true...? I want to get a gray scale, encoded video output from the *Theora* encoder while the input video is getting from a web cam (color input and gray scale

Hello all, When I'm doing something like: yuv_buffer yuv; theora_decode_YUVout(&td,&yuv); I'm guessing a bunch of stuff gets newed/malloced for yuv.y, yuv.u, and yuv.u. Who is responsible for deleting/freeing that stuff? Cheers, Kos.

hi folks! once again i am trying to decode a yuv_buffer to a 24 bit RGB buffer. last time nobody seemed willing to tell me how to do this, so i am trying again. i try to make my questions more simple. what i need to know is: how many bytes are in each y, u, v array? what for are these strides? what exactly is a "plane" in a frame, and what does it do? what i want to achieve is

Hi, The documentation for the libtheora API is a little bit sparse - for example, information about whether yuv_buffer structs should be managed by the user or the library is missing. From talking to derf, and from what I can see in the example files, the user allocates the struct but not the luma/chroma buffers on decode; and the user allocates both the struct and the luma/chroma buffers on

Hello all. I've been playing around with theora since it first entered CVS, and I like what I'm seeing. Today I've been fixing xine's theoraplugin to understand theora_info.frame_{width,height} and theora_info.offset_{x,y}. I only got it working after some experimenting and basically copying the code from player_example. A few questions related to this: 1. What are the legal