search for: yuv420

Hello. I'm a theora newbie... I see it accept video frames in some differents YUV formats. How theora manage them internally? I mean: if i encode the same video twice, first time encoding it with YUV444 packets and then with YUV420, will second video be smaller than first (due to subsampling...)? Or theora compress them in the same way? Thanks in advance, A. F.

Hello, I want to make a program to extract frame from a theora movie as images. I tried with the decoding example located at theora web site (dump_video.c. I use it to extract a frame as yuv image but when I try to convert it to ppm with yuvtoppm program i obtain a strange image ( see http://poux.be/tmp/file.ppm ). I think it's a problem with the byte order for yuv, but don't I don't

...Right now, my compression scheme for the wavelet coefficients is equivalent to ZPAQ -method 4 (but very faster).With my new ideas, I think I can improve compression by 1-2%, which will put my scheme on the same level as ZPAQ -method 5! I haven't made much research, but I would also need better YUV420 2x2 up/down-sampling functions (mines are too basic and not really good).If you would know good ones, do not hesitate to contact me.Maybe a Daala developer could point me to the ones used for Daala still image? With all this, I think I could make a 0.1.4 version, but I don't know when it will...

...t,... There are some important parts to be done: like testing new wavelet transforms like directional, (edge-) oriented wavelets, some advanced and state-of-the-art improvements to the compression schemes (for wavelet DC image, wavelet coefficients and residual coding), new quantization scheme, new YUV420 down/upsampling, container format,.... For now, I don't have the time to do all this, but if you want to see it done (that I work full-time on it) and can sponsorise me (via Xiph.org if you want) do not hesitate to contact me. If you didn't find time to test the codec and want to see some...

...results? Second, is it acceptable that a codec is better than another in 60% of the cases but perform quite badly in 5% of the cases? I would be very interested in your opinion on this subject. Very quickly to finish, my codec really need improvements at some stages.It really needs to have better YUV420 down/upsampling algorithms (don't know about image Super-Resolution upsampling with machine learning or convolutional neural network, they're excellent but too slow for image compression I fear..., there are also other algorithms that are very good)... For the lower quality settings (-l1,-l...

...e conclusion that directional transforms will bring marginal improvement, not significant in the case of my compression codec.This also confirms what I have read from the Rududu author who tested directional wavelets in his codec without luck. I have potentially found a very good candidate for the YUV420 2x2 upsampling.I haven't studied the impact of this processing on the codec, but I believe that better downsampling and upsampling algorithms for U and V components will bring better quality to the codec.Here is the upsampling I'm thinking of, the demo page is very impressive: https://kdepe...

Hi, I've been trying to use libtheora-experimental (libtheoraenc and libtheoradec) to encode a webcam feed in real-time, to be decoded also in realtime by a second party via XXX-IP, with - unfortunately - not so good results. I'm using custom written functions to convert from RGB8 to YUV420 and back and, although not much processor-efficient, they do what they're supposed to nicely. Unfortunatelly, I get a lot of "block-artifacts" in the process. With one webcam, the image starts all "blocky" and then, if you keep the image still, it gets better. If you move...

Hi all, I've been playing with Theora this week and have hacked together a test program (http://www.firestorm.cx/live1/) that can encode live video (no audio) from a V4L* source that supports the YUV420 pixel format. Now encoding Theora ain't exactly a speedy process, and sometimes frames get lost during capturing. What I'd like to be able to do is tell libtheora that the next few frames are missing (or are duplicates of the last frame) without having to re-submit the same frame more than...

> But chroma subsampling? no. And this is where much of the complexity > comes. > > If we were to combine them, we would be, essentially, doing it something > like > this: > Value Meaning > 0 RGB > 1 YUV444 > 2 YUV422 > 3 YUV420 > 4 YUV411 > ..... Yes. > And then spend an additional field on bits/channel, whereas both chroma > channels > in YUV is are going to have the same size. Oh, please, let there not be > an > exception to this. Well depending what you want to do... not only are there...

...as resolution, framerate, prehaps even interlace and aspect ratio... But chroma subsampling? no. And this is where much of the complexity comes. If we were to combine them, we would be, essentially, doing it something like this: Value Meaning 0 RGB 1 YUV444 2 YUV422 3 YUV420 4 YUV411 ..... And then spend an additional field on bits/channel, whereas both chroma channels in YUV is are going to have the same size. Oh, please, let there not be an exception to this. Now, keep in mind, that calling two codecs different is a conceptual one. If the difference be...

...as resolution, framerate, prehaps even interlace and aspect ratio... But chroma subsampling? no. And this is where much of the complexity comes. If we were to combine them, we would be, essentially, doing it something like this: Value Meaning 0 RGB 1 YUV444 2 YUV422 3 YUV420 4 YUV411 ..... And then spend an additional field on bits/channel, whereas both chroma channels in YUV is are going to have the same size. Oh, please, let there not be an exception to this. Now, keep in mind, that calling two codecs different is a conceptual one. If the difference be...

> But chroma subsampling? no. And this is where much of the complexity > comes. > > If we were to combine them, we would be, essentially, doing it something > like > this: > Value Meaning > 0 RGB > 1 YUV444 > 2 YUV422 > 3 YUV420 > 4 YUV411 > ..... Yes. > And then spend an additional field on bits/channel, whereas both chroma > channels > in YUV is are going to have the same size. Oh, please, let there not be > an > exception to this. Well depending what you want to do... not only are there...

...he NHW Project so I am not able to really work on it currently, I think paying an engineer for that purpose is too expensvie, so I will try to make a (complete) TODO list to finish the project and give it to the open-source commuity. First thoughts, there are, coding lower quality settings, better YUV420 2x2 up- and down- samplings, a dozen of (fast) algorithm refinements/tunings, process on rows and columns for the DWT and suppress image transposition, some advanced improvements to the compression schemes, and when all that is done, adapt the codec to any size of image, and then I think the NHW co...

...buffer and framebuffer for planes modetest: destroy the cursor bo modetest: fix the arguments of the MAKE_RGB_INFO define Neil Roberts (1): intel: Merge latest i915_drm.h Rob Clark (2): modeprint: add missing encoder/connector type names modetest: fix allocation for yuv420/yvu420 Tobias Jakobi (1): modetest: initialize handles/pitches in set_plane() Tvrtko Ursulin (1): intel: Leak the userptr test bo git tag: libdrm-2.4.61 http://dri.freedesktop.org/libdrm/libdrm-2.4.61.tar.bz2 MD5: c3d31138d63e0edde3f5b93cd88fb93a libdrm-2.4.61.tar.bz2 SHA1: fce703...

...rt of this is our screen capture tool, which works by querying drm for crtcs, planes, and fbs. Unfortunately, there is only limited information available via drmModeGetFB(), which often wrong information when drmModeAddFB2() was used to create the fbs. For example, if the pixel format is NV12 or YUV420, the fb returned knows nothing about the additional buffer planes required by these formats. Ideally, we would like a function (e.g. drmModeGetFB2) to return information symmetric with drmModeAddFB2 including the pixel format id, buffer plane information etc. </snip> ChromeOS has needed thi...

...theora_decoder.c The only function to really consider is get_frame() which takes a (const) char *URI (actually the current version really only takes a local file name), and an int64_t frame number and returns the output in void *pixel_data[3] which should be pre-allocated to take a correctly sized YUV420 frame. The rest is just internal functions or decoration, apart from get_clip_data() which returns a struct with all the details about (const) char *URI. I only implemented video (theora) decoding, but it should be fairly easy to implement audio decoding from the same pages. Yes, it is a bit compl...

On Thu, Aug 30, 2012 at 6:33 PM, Konrad Rzeszutek Wilk <konrad@kernel.org>wrote: Hi, > > I''ve just upgraded a server of mine from a Core i3 2100T to an i7 3770, > in order > > to do full virtualization with VTd. > > > > I''m using kernel 3.5.2 and Xen from git://xenbits.xen.org/xen.git @ > commit > >

This is the beginnings of HDMI 2.0 support. All of the "extra" features are left out, such as 12/16bpc, YUV420, etc. I've verified that with this code, a GP108 (GT1030) can switch between 4k at 60 and 1920x1080 at 60 on a LG 4K TV. Further, I've verified via i2c tools, that the SCDC writes really do happen. I suspect that the patch for keeping track of the high-speed TMDS setting is somehow off, e...

...ur screen capture tool, which works by querying drm for crtcs, planes, and > fbs. Unfortunately, there is only limited information available via > drmModeGetFB(), which often wrong information when drmModeAddFB2() was used > to create the fbs. For example, if the pixel format is NV12 or YUV420, > the fb returned knows nothing about the additional buffer planes required > by these formats. Ideally, we would like a function (e.g. drmModeGetFB2) > to return information symmetric with drmModeAddFB2 including the pixel > format id, buffer plane information etc. > </snip&gt...

...<br>The only function to really consider is get_frame() which takes a (cons= t) char *URI (actually the current version really only takes a local file n= ame), and an int64_t frame number and returns the output in void *pixel_dat= a[3] which should be pre-allocated to take a correctly sized YUV420 frame. = The rest is just internal functions or decoration, apart from get_clip_data= () which returns a struct with all the details about (const) char *URI. I o= nly implemented video (theora) decoding, but it should be fairly easy to im= plement audio decoding from the same pages.<br> <...