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Autres articles (26)
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Participer à sa traduction
10 avril 2011Vous pouvez nous aider à améliorer les locutions utilisées dans le logiciel ou à traduire celui-ci dans n’importe qu’elle nouvelle langue permettant sa diffusion à de nouvelles communautés linguistiques.
Pour ce faire, on utilise l’interface de traduction de SPIP où l’ensemble des modules de langue de MediaSPIP sont à disposition. ll vous suffit de vous inscrire sur la liste de discussion des traducteurs pour demander plus d’informations.
Actuellement MediaSPIP n’est disponible qu’en français et (...) -
Supporting all media types
13 avril 2011, parUnlike most software and media-sharing platforms, MediaSPIP aims to manage as many different media types as possible. The following are just a few examples from an ever-expanding list of supported formats : images : png, gif, jpg, bmp and more audio : MP3, Ogg, Wav and more video : AVI, MP4, OGV, mpg, mov, wmv and more text, code and other data : OpenOffice, Microsoft Office (Word, PowerPoint, Excel), web (html, CSS), LaTeX, Google Earth and (...)
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Encoding and processing into web-friendly formats
13 avril 2011, parMediaSPIP automatically converts uploaded files to internet-compatible formats.
Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
All uploaded files are stored online in their original format, so you can (...)
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Simply beyond ridiculous
For the past few years, various improvements on H.264 have been periodically proposed, ranging from larger transforms to better intra prediction. These finally came together in the JCT-VC meeting this past April, where over two dozen proposals were made for a next-generation video coding standard. Of course, all of these were in very rough-draft form ; it will likely take years to filter it down into a usable standard. In the process, they’ll pick the most useful features (hopefully) from each proposal and combine them into something a bit more sane. But, of course, it all has to start somewhere.
A number of features were common : larger block sizes, larger transform sizes, fancier interpolation filters, improved intra prediction schemes, improved motion vector prediction, increased internal bit depth, new entropy coding schemes, and so forth. A lot of these are potentially quite promising and resolve a lot of complaints I’ve had about H.264, so I decided to try out the proposal that appeared the most interesting : the Samsung+BBC proposal (A124), which claims compression improvements of around 40%.
The proposal combines a bouillabaisse of new features, ranging from a 12-tap interpolation filter to 12thpel motion compensation and transforms as large as 64×64. Overall, I would say it’s a good proposal and I don’t doubt their results given the sheer volume of useful features they’ve dumped into it. I was a bit worried about complexity, however, as 12-tap interpolation filters don’t exactly scream “fast”.
I prepared myself for the slowness of an unoptimized encoder implementation, compiled their tool, and started a test encode with their recommended settings.
I waited. The first frame, an I-frame, completed.
I took a nap.
I waited. The second frame, a P-frame, was done.
I played a game of Settlers.
I waited. The third frame, a B-frame, was done.
I worked on a term paper.
I waited. The fourth frame, a B-frame, was done.
After a full 6 hours, 8 frames had encoded. Yes, at this rate, it would take a full two weeks to encode 10 seconds of HD video. On a Core i7. This is not merely slow ; this is over 1000 times slower than x264 on “placebo” mode. This is so slow that it is not merely impractical ; it is impossible to even test. This encoder is apparently designed for some sort of hypothetical future computer from space. And word from other developers is that the Intel proposal is even slower.
This has led me to suspect that there is a great deal of cheating going on in the H.265 proposals. The goal of the proposals, of course, is to pick the best feature set for the next generation video compression standard. But there is an extra motivation : organizations whose features get accepted get patents on the resulting standard, and thus income. With such large sums of money in the picture, dishonesty becomes all the more profitable.
There is a set of rules, of course, to limit how the proposals can optimize their encoders. If different encoders use different optimization techniques, the results will no longer be comparable — remember, they are trying to compare compression features, not methods of optimizing encoder-side decisions. Thus all encoders are required to use a constant quantizer, specified frame types, and so forth. But there are no limits on how slow an encoder can be or what algorithms it can use.
It would be one thing if the proposed encoder was a mere 10 times slower than the current reference ; that would be reasonable, given the low level of optimization and higher complexity of the new standard. But this is beyond ridiculous. With the prize given to whoever can eke out the most PSNR at a given quantizer at the lowest bitrate (with no limits on speed), we’re just going to get an arms race of slow encoders, with every company trying to use the most ridiculous optimizations possible, even if they involve encoding the frame 100,000 times over to choose the optimal parameters. And the end result will be as I encountered here : encoders so slow that they are simply impossible to even test.
Such an arms race certainly does little good in optimizing for reality where we don’t have 30 years to encode an HD movie : a feature that gives great compression improvements is useless if it’s impossible to optimize for in a reasonable amount of time. Certainly once the standard is finalized practical encoders will be written — but it makes no sense to optimize the standard for a use-case that doesn’t exist. And even attempting to “optimize” anything is difficult when encoding a few seconds of video takes weeks.
Update : The people involved have contacted me and insist that there was in fact no cheating going on. This is probably correct ; the problem appears to be that the rules that were set out were simply not strict enough, making many changes that I would intuitively consider “cheating” to be perfectly allowed, and thus everyone can do it.
I would like to apologize if I implied that the results weren’t valid ; they are — the Samsung-BBC proposal is definitely one of the best, which is why I picked it to test with. It’s just that I think any situation in which it’s impossible to test your own software is unreasonable, and thus the entire situation is an inherently broken one, given the lax rules, slow baseline encoder, and no restrictions on compute time.
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FFMPEG compiled binaries don't run using MinGW
9 juin 2015, par Paul KnopfI am trying to build windows executables/dlls for Windows XP, and they are not working. They are the correct architecture. They run fine on my Windows 8 device machine.
I used dependency walker to find missing DLLs, and all were present.
Here are the compiled executables I am trying to run.
I ran the windows build script for ffmpeg.
Here is a
dumpbin /headers ffmpeg.exeMicrosoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file ffmpeg.exe
PE signature found
File Type: EXECUTABLE IMAGE
FILE HEADER VALUES
14C machine (x86)
7 number of sections
51A40 time date stamp Sun Jan 04 15:53:20 1970
0 file pointer to symbol table
0 number of symbols
E0 size of optional header
32F characteristics
Relocations stripped
Executable
Line numbers stripped
Symbols stripped
Application can handle large (>2GB) addresses
32 bit word machine
Debug information stripped
OPTIONAL HEADER VALUES
10B magic # (PE32)
2.25 linker version
41400 size of code
4FA00 size of initialized data
1200 size of uninitialized data
14E0 entry point (004014E0)
1000 base of code
43000 base of data
400000 image base (00400000 to 00456FFF)
1000 section alignment
200 file alignment
4.00 operating system version
1.00 image version
4.00 subsystem version
0 Win32 version
57000 size of image
400 size of headers
597A9 checksum
3 subsystem (Windows CUI)
140 DLL characteristics
Dynamic base
NX compatible
200000 size of stack reserve
1000 size of stack commit
100000 size of heap reserve
1000 size of heap commit
0 loader flags
10 number of directories
0 [ 0] RVA [size] of Export Directory
51000 [ 36F0] RVA [size] of Import Directory
0 [ 0] RVA [size] of Resource Directory
0 [ 0] RVA [size] of Exception Directory
0 [ 0] RVA [size] of Certificates Directory
0 [ 0] RVA [size] of Base Relocation Directory
0 [ 0] RVA [size] of Debug Directory
0 [ 0] RVA [size] of Architecture Directory
0 [ 0] RVA [size] of Global Pointer Directory
56004 [ 18] RVA [size] of Thread Storage Directory
0 [ 0] RVA [size] of Load Configuration Directory
0 [ 0] RVA [size] of Bound Import Directory
517F0 [ 6C4] RVA [size] of Import Address Table Directory
0 [ 0] RVA [size] of Delay Import Directory
0 [ 0] RVA [size] of COM Descriptor Directory
0 [ 0] RVA [size] of Reserved Directory
SECTION HEADER #1
.text name
412BC virtual size
1000 virtual address (00401000 to 004422BB)
41400 size of raw data
400 file pointer to raw data (00000400 to 000417FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
60500060 flags
Code
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Execute Read
SECTION HEADER #2
.data name
19C virtual size
43000 virtual address (00443000 to 0044319B)
200 size of raw data
41800 file pointer to raw data (00041800 to 000419FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0700040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #3
.rdata name
A7D8 virtual size
44000 virtual address (00444000 to 0044E7D7)
A800 size of raw data
41A00 file pointer to raw data (00041A00 to 0004C1FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
40700040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Only
SECTION HEADER #4
.bss name
1200 virtual size
4F000 virtual address (0044F000 to 004501FF)
0 size of raw data
0 file pointer to raw data
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0700080 flags
Uninitialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #5
.idata name
36F0 virtual size
51000 virtual address (00451000 to 004546EF)
3800 size of raw data
4C200 file pointer to raw data (0004C200 to 0004F9FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #6
.CRT name
3C virtual size
55000 virtual address (00455000 to 0045503B)
200 size of raw data
4FA00 file pointer to raw data (0004FA00 to 0004FBFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #7
.tls name
20 virtual size
56000 virtual address (00456000 to 0045601F)
200 size of raw data
4FC00 file pointer to raw data (0004FC00 to 0004FDFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
Summary
1000 .CRT
2000 .bss
1000 .data
4000 .idata
B000 .rdata
42000 .text
1000 .tlsWhen I attempt to run the executable on XP, it just closes. There is no "missing dll" messages, nor anything in the event viewer.
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FFMPEG compiled binaries don't run on XP using MinGW
10 juin 2015, par Paul KnopfI am trying to build windows executables/dlls for Windows XP, and they are not working. They are the correct architecture. They run fine on my Windows 8 device machine.
I used dependency walker to find missing DLLs, and all were present.
Here are the compiled executables I am trying to run.
I ran the windows build script for ffmpeg.
Here is a
dumpbin /headers ffmpeg.exeMicrosoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file ffmpeg.exe
PE signature found
File Type: EXECUTABLE IMAGE
FILE HEADER VALUES
14C machine (x86)
7 number of sections
51A40 time date stamp Sun Jan 04 15:53:20 1970
0 file pointer to symbol table
0 number of symbols
E0 size of optional header
32F characteristics
Relocations stripped
Executable
Line numbers stripped
Symbols stripped
Application can handle large (>2GB) addresses
32 bit word machine
Debug information stripped
OPTIONAL HEADER VALUES
10B magic # (PE32)
2.25 linker version
41400 size of code
4FA00 size of initialized data
1200 size of uninitialized data
14E0 entry point (004014E0)
1000 base of code
43000 base of data
400000 image base (00400000 to 00456FFF)
1000 section alignment
200 file alignment
4.00 operating system version
1.00 image version
4.00 subsystem version
0 Win32 version
57000 size of image
400 size of headers
597A9 checksum
3 subsystem (Windows CUI)
140 DLL characteristics
Dynamic base
NX compatible
200000 size of stack reserve
1000 size of stack commit
100000 size of heap reserve
1000 size of heap commit
0 loader flags
10 number of directories
0 [ 0] RVA [size] of Export Directory
51000 [ 36F0] RVA [size] of Import Directory
0 [ 0] RVA [size] of Resource Directory
0 [ 0] RVA [size] of Exception Directory
0 [ 0] RVA [size] of Certificates Directory
0 [ 0] RVA [size] of Base Relocation Directory
0 [ 0] RVA [size] of Debug Directory
0 [ 0] RVA [size] of Architecture Directory
0 [ 0] RVA [size] of Global Pointer Directory
56004 [ 18] RVA [size] of Thread Storage Directory
0 [ 0] RVA [size] of Load Configuration Directory
0 [ 0] RVA [size] of Bound Import Directory
517F0 [ 6C4] RVA [size] of Import Address Table Directory
0 [ 0] RVA [size] of Delay Import Directory
0 [ 0] RVA [size] of COM Descriptor Directory
0 [ 0] RVA [size] of Reserved Directory
SECTION HEADER #1
.text name
412BC virtual size
1000 virtual address (00401000 to 004422BB)
41400 size of raw data
400 file pointer to raw data (00000400 to 000417FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
60500060 flags
Code
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Execute Read
SECTION HEADER #2
.data name
19C virtual size
43000 virtual address (00443000 to 0044319B)
200 size of raw data
41800 file pointer to raw data (00041800 to 000419FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0700040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #3
.rdata name
A7D8 virtual size
44000 virtual address (00444000 to 0044E7D7)
A800 size of raw data
41A00 file pointer to raw data (00041A00 to 0004C1FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
40700040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Only
SECTION HEADER #4
.bss name
1200 virtual size
4F000 virtual address (0044F000 to 004501FF)
0 size of raw data
0 file pointer to raw data
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0700080 flags
Uninitialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #5
.idata name
36F0 virtual size
51000 virtual address (00451000 to 004546EF)
3800 size of raw data
4C200 file pointer to raw data (0004C200 to 0004F9FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #6
.CRT name
3C virtual size
55000 virtual address (00455000 to 0045503B)
200 size of raw data
4FA00 file pointer to raw data (0004FA00 to 0004FBFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
SECTION HEADER #7
.tls name
20 virtual size
56000 virtual address (00456000 to 0045601F)
200 size of raw data
4FC00 file pointer to raw data (0004FC00 to 0004FDFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0300040 flags
Initialized Data
RESERVED - UNKNOWN
RESERVED - UNKNOWN
Read Write
Summary
1000 .CRT
2000 .bss
1000 .data
4000 .idata
B000 .rdata
42000 .text
1000 .tlsWhen I attempt to run the executable on XP, it just closes. There is no "missing dll" messages, nor anything in the event viewer.
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