similar to: VP3 IDCT

So, in preparation for some decoder optimization work planned by Rudolf Marek, the subject of the size of the registers needed in the IDCT came up. The current spec language ensures that the result is exactly compatible with the C code for VP3. This language requires that some of the arguments to the multiplies be 17 or 18 bits, because they need to hold the sum or difference of two 16-bit

Hi. I am trying to find calls of idct/fdct.c functions by tracing png2theora.c calls. But found only: analyze.c:oc_dct_cost2() Where and when idct/fdct/mmxidct/mmxfdct.c functions are used? Mentions of "dct" word: ==== pacify at optima-amd64:/usr/src/libtheora-1.2.0alpha1/lib$ grep dct *.c | cut -f1 -d":" | uniq -c ???? 19 analyze.c ???? 28 decode.c ???? 22 encode.c ????? 4

Hi The Theora specification states, in section 7.9.3 ("The 1D Inverse DCT") steps 14-16: 14. Assign T[5] the value T[4] - T[5]. 15. Truncate T[5] to a 16-bit representation by dropping any higher-order bits. 16. Assign T[5] the value C4 * (-T[5]) >> 16. However, the relevant section of code in the reference decoder (lib/dec/idct.c line 50) is:

just added to the WIKI: * Ideas with some concensus after discussion on IRC, it was provisionally agreed (by those present at the time) that Theora should support arbitrary pixel sizes (presently it is limited to multiples of 16 both horizontally and vertically). It is felt that this can be achieved with minimal pain by adding four values to the page header, immediately following the present

Hi, Check it out-- another update in the space of a week: http://home.pcisys.net/~melanson/codecs/vp3-format.txt v0.4: March 2, 2004 - renamed and expanded section "Initializing The Quantization Matrices" - outlined section "Reconstructing The Frame" - moved Theora Differences Appendix to its own section entitled "Theora Specification" - added Appendix:

Hi, So it took a little while to get here but VP3 through ffmpeg is finally starting to achieve viewable results. It partially works right now. Keyframes only. And monochrome. Oh, and the picture is upside down (something I did not realize about VP3 until I let it fly just now). Anyway, here is a picture of ffmpeg's VP3 decoder in action using xine:

(Cross posted to theora-dev@xiph.org and ffmpeg-devel@mplayerhq.hu) I am working towards adding Theora encoding support to libavcodec in FFmpeg. I am doing this by simply calling libtheora from libavcodec. I am at the point where I can execute: "./ffmpeg -v 100 -i test.wmv -f avi -an -vcodec theora -b 1000000 -y test.avi" I get some whirring and an output file written. My calls to

I try to merge VP3's mmx decoder into theora. http://kyoto.cool.ne.jp/vp3/developers/theora-alpha3-MMXd-src.zip You can see the change by searching the keyword "_UsingMMX_" in all lib folder's file. From VP3???YO vp3@go8.enjoy.ne.jp

Hi, Keep up the good work! The file sizes of Theora's output is amazing! I have just joined the list, and would like to contribute to the

Hi, Since a number of people are eager to try out the native VP3 decoder in xine, I have made a patch available, bz2-compressed: http://www.pcisys.net/~melanson/codecs/xine-vp3-decoder-patch.bz2 To work with this patch: 1) Get the latest xine-lib from CVS. Visit this page for more details: http://sourceforge.net/cvs/?group_id=9655 The module name is xine-lib, but you will also need

Hi, I have been on a documentation kick recently. I finally updated my VP3 format document tonight: http://www.pcisys.net/~melanson/codecs/vp3-format.txt v0.2: October 9, 2003 - expanded section "Reversing the DC Prediction" - added Appendix B: Theora Differences Feel free to look it over and point out any glaring mistakes. I can't wait to see how much sense it makes to

Hi, I have been working with VP3 for some time now. Dan Miller from On2 just told me about this list. A few months ago, I managed to get On2's VP3 source snapshot to compile under Linux, a feat that many have apparently attempted and quickly abandoned. I compiled a small console app and the results of the experiment are explained here:

I hope this list is small enough for not beeing banned when introducing oneself. So... Hi, I just subscribed to the theora-lists. I'm from the XVID project, so I know a deal about video and MPEG-4 in particular, but nothing about Vorbis/Theora etc., That's why I'm here, because I'm interested in patent-free alternatives. I guess there is no documentation of the current status

Hi people, As I said before: I did the IDCT to run on the FPGA. My friends from university did the Reconstruction routines running on the FPGA. I'm helping with the LoopFilter, and it is almost there. (all VHDL) I did a small profiling of the libTheora running on a Altera Stratix II device: The processor used was the NIOS II with 8Kb of data and instruction cache, branch prediction and

The vp3 / theora decoder in FFmpeg project received a major speedup: http://multimedia.cx/eggs/profiling-and-optimizing-theora/#comment-150751 http://git.ffmpeg.org/?p=ffmpeg;a=commit;h=6e8061980c9a18a0eb9802f5dc5becc349066680 http://git.ffmpeg.org/?p=ffmpeg;a=commit;h=8476744ba50d26a3e188def192cd9086b0f781d7 http://git.ffmpeg.org/?p=ffmpeg;a=commit;h=a51faef9b61bd80499a28322802ef4b22be44d43

Hi, Sorry for taking so long with this, but I finally committed a first pass of my own VP3 decoder to the ffmpeg codebase. You can browse the source here: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/ffmpeg/ffmpeg/libavcodec/ vp3.c and vp3data.h are the files in question. Attached is a message I sent to the ffmpeg-devel list about the new decoder and its present shortcomings.

1) What are you doing "mathematically" in a procedure x86/x86enquant: oc_enc_quantize_sse2()? This - the assembler code, and I do not understand mathematically - that's going on there. --- A: 120 121 28 73 -20 -99 -98 -100 123 122 112 108 73 -32 -102 -98 123 123 117 121 100

I have tried to add a plunging to the "libtheora-1.0beta2" (network bandwidth measuring component was added) and Got it success for some far now the problem is when it is added the encoding process get extremely slow (around 20 seconds delay). I think that the problem is with my modified Makefile (some flag may have missed). the following is my modified Makefile.am which is in the

Hi, I don't know how much of the old VP3 codebase is incorporated into Theora. I wrote ffmpeg's VP3 decoder from scratch but eventually ported in the original VP3 IDCT function. A BSD conflict cropped up that I thought I would pass along. -- -Mike Melanson <p>---------- Forwarded message ---------- Date: Wed, 10 Sep 2003 13:06:37 -0700 (PDT) From: Steven M. Schultz

Dan, In reviewing the code, derf came across the DCSearchPoints array in QuadCodeDisplayFragments(), encode.c:696. It looks like it specifies a search order for nearby coded fragments for prediction if there isn't a nearest neighbor. However, the upper search bound is defined as *0*, so the search loop (line 917) is never executed and it always falls back to the last coded fragment.