Feb 122016
 

H.265/HEVC logo1.) Giving you the binaries:

Just recently I tried to give the x265 H.265/HEVC video encoder another chance to prove itself, because so far I’ve been using x264, so H.264/AVC. x264 does a really good job, but given that the marketing guys are talking about colossal efficiency/quality gains with H.265, I thought I’d put that to the test once again. It was quite easy to compile the software on my CentOS 6.7 Linux, but my old XP x64 machine proved to be a bit tricky.

But, after a bit of trial and error and getting used to the build toolchain, I managed to compile a seemingly stable version from the latest snapshot:

x265 cli, showing the version info

x265 cli, showing its version info.

Update 2: And here comes my first attempt to build an x86_64 multilib binary, that can encode H.265 at 8-bit, 10-bit and 12-bit per pixel color depths. You may wish to use this if you need more flexibility (like using 12-bit for PC only and 8- or 10-bit for a broader array of target systems like TVs, cellphones etc.). It’s currently still being tested for a short encoding run. You can specify the desired color depth with the parameter -D, like -D 8, -D 10 or -D 12:

Update: And here are the newer 1.9 versions, built from source code directly from the [MulticoreWare] (=the developers) servers. I haven’t tested these yet, but given that I configured & compiled them in the same way as before, they “should work™”:

And the old 1.7 versions from the Videolan servers:

So this has been built with MSVC10 and yasm 1.3.0 on Windows XP Pro x64 SP2, meaning this needs the Microsoft Visual C++ 2010 runtime. You can get it from Microsoft if you don’t have it yet: [32-bit version], [64-bit version]. v1.7 tested for basic functionality on XP 32-bit and tested for encoding on XP x64. The 32-bit version only supports 8-bit per pixel, which is default for x264 as well. The 64-bit versions support either 8-, 10- or 12 bits per pixel. Typically, higher internal precision per pixel results in finer gradients and less banding. 8-/10-bit is default for H.265/HEVC. 12-bit will likely not be supported by any hardware players, just as it was with 10-bit H.264/AVC before.

You may or may not know it, but as of now, x265 cannot be linked against either ffmpeg or libav, so it can only read raw input. To “feed” it properly you need either a frame server like [AviSynth] in combination with the pipe tool [Avs4x265], or a decoder that can pipe raw YUV to x265. I went for the latter version, because I already have libav+fdkaac compiled for Windows to get the avconv.exe binary. It’s quite similar to ffmpeg.

This I can only provide as a 64-bit binary, as I’m not going to build it for 32-bit Windows anytime soon I guess, so here you go:

This was compiled with GCC 4.9.2 and yasm 1.3.0 on CygWin x64. To use the two together, add the locations of your EXE files (avconv.exe and x265.exe) to your search path. Then, you can feed arbitrary video (VC1, H.264/AVC, MPEG-2, whatever) to x265. An example for a raw H.264/AVC input stream using the 64-bit versions of the software:

avconv -r 24000/1001 -i video-input.h264 -f yuv4mpegpipe -pix_fmt yuv420p - 2>NUL |^
 x265 - --wpp --y4m -D 12 -p slower --bframes 16 --bitrate 2000 --crf 18 --sar 1^
 --range full -o video-output.h265

Or another, reading some video stream from an MKV container, disabling audio and subtitles:

avconv -r 24000/1001 -i video-input.mkv -f yuv4mpegpipe -pix_fmt yuv420p -an -sn^
 - 2>NUL | x265 - --wpp --y4m -D 12 -p slower --bframes 16 --bitrate 2000 --crf 18^
 --sar 1 --range full -o video-output.h265

Just remove the carets and line breaks to make single-line commands out of those if preferred. To understand all the options, make yourself some readmes like this: avconv -h full > avconv-readme.txt and x265 --log-level full --help > x265-readme.txt or read the documentation online.

2.) How to compile by yourself:

2a.) Prerequisites:

I won’t describe how to build libav here, but just the x265 part. First of all, you need some software to be able to do this, some of it free, other not so much (unless you can swap MSVC with MSYS, I didn’t try that):

  • [cmake] (I used version 2.8.12 because that’s roughly what I have on Linux.)
  • [Mercurial] (Needed to fetch the latest version from x265′ versioning system. I used the latest Inno Setup installer.)
  • [yasm] (Put yasm.exe in your search path and you’re fine. This is optional, but you really want this for speed reasons.)
  • [Microsoft Visual Studio] (Use 2010 if you’re on Windows XP. Supported versions: 2008/VC9, 2010/VC10, 2012/VC11 & 2013/VC12)
  • [x265 source code] (Enter a target download path and use Mercurials hg.exe like hg clone https://bitbucket.org/multicoreware/x265 to fetch it)

2b.) Preparation of the solution:

Usually, you would use cmake to have it compile your entire project, but in this case it’ll build Visual Studio project files and a solution file for us. To do this, enter the proper build path. In my case I’m using Visual Studio 2010, so VC10, and I’d like to build the 64-bit version, so with the unpacked x265 source, I’d enter its subdirectory build\vc10-x86_64\ and then run the generation script: .\make-solutions.bat:

make-solutions.bat preparing cmake for us

make-solutions.bat is preparing cmake for us.

There are several things you need to make sure here: First, if you’re on Windows XP or Windows Vista, you need to toggle the WINXP_SUPPORT flag. Also, if you’re compiling for a 64-bit target, you may wish to enable HIGH_BIT_DEPTH as well to get to either 10-bit or even 12-bit per pixel other than just 8. The 32-bit code doesn’t seem to support high bit dephts right now.

Then there is one more important thing; With CMAKE_CONFIGURATION_TYPES set to Debug;Release;MinSizeRel;RelWithDebInfo, my build was unstable, throwing errors during encoding, like x265 [error]: scaleChromaDist wrap detected dist: -2029735662 lambda: 256. Setting CMAKE_CONFIGURATION_TYPES to just Release solved that problem! So you may wish to do the same.

Make sure ENABLE_CLI and ENABLE_ASSEMBLY are checked as well, then click Configure. If you’re building with high bit depth support, you’ll be presented with another option, MAIN12. You should enable this to get Main12 profile support in case you’re planning to build a 12-bit encoder. If you don’t pick it, you’ll get a 10-bit version instead, staying within Blu-Ray 4K specifications. After that, click Configure again. Generally, you need to click Configure unless no more red stuff pops up, then click Generate.

2c.) Compiling and installing the solution:

Load the resulting solution file x265.sln into Microsoft Visual Studio, then right click ALL_BUILD and pick Build. This will compile x265. If you want to install it from the IDE as well, right click INSTALL and select Build. This will install x265 in %PROGRAMFILES%\x265\ with the binary sitting in %PROGRAMFILES%\x265\bin\:

Microsoft Visual Studio 2010, ready to compile the x265 solution generated by cmake

Microsoft Visual Studio 2010 with the x265 solution generated by cmake loaded, compiled and installed.

3.) Running it:

Now we can feed x265 some raw YUV files like this, after adding x265.exe to the search path:

x265 encoding a raw YUV file to H.265/HEVC

x265 encoding a raw YUV 4:2:0 file to H.265/HEVC (The options given to x265 may actually suck, I’m still in the learning process).

Or we can use a decoder to feed it arbitrary video formats, even from MKV containers, like shown in the beginning. ffmpeg or avconv can decode pretty much anything, and then pipe it into x265 as raw YUV 4:2:0:

x265 being fed a H.264/AVC bitstream by avconv

x265 being fed a H.264/AVC bitstream by avconv.

And that’s it! Now all I need is some 18-core beast processor to handle the extreme slowness of the encoder at such crazy settings. When going almost all-out, it’s easily 10 times as slow as x264 (at equally insane settings)! Or maybe I can get access to some rack server with tons of cores or something… :roll:

Update: All x265 releases have now been consolidated on [this page]! All future XP- and XP x64-compatible releases of x265 plus a relatively recent version of avconv to act as a decoder for feeding x265 with any kind of input video streams will be posted there as well.

Jun 292012
 

I have once written an FTP logfile analyzer in Perl. That analyzer collects data like transferred megabytes and connections, groups it per user and publishes it on the web in somewhat simple, neat HTML. Sounds nice? Well, it is! There is only one problem that bugged me for ages now. The logfile is growing and growing, and since my script is optimized for constant non-growing memory consumption, it’s somewhat slow. Still faster AND far smaller as well as far more scalable than [sustat] ever was, but it’s running on a Pentium PRO, i mean…

Actually, I am updating the web statistics every hour and with my ~60MB logfile processing takes almost 10 minutes when doing the full logfile. At some point it will take 30 minutes, then the full hour etc., unacceptable.

So, my idea to solve it: Do it incrementally! Just process the whole file once, generate an intermediate data file and a byte address index of every line in the log file (necessary for efficient seeking), and the next time continue where we left off. And here is where the problem lies. I was trying to generate a binary index file consisting of 4 byte large packed data elements. Each element can hold a 32-bit unsigned integer, and that number is the corresponding line number in the log file, the one you would want to seek to, when updating the stats in an incremental fashion.

So I can just say, “I want to seek to line number 1.000.000”. Then the code will seek to the (1.000.000 × 4)th byte in the index file, and get the 1.000.000th data element. In that element, – after calling unpack() on it – lies the byte address for line number 1.000.000 in the log file. Now you can seek there and process any newly added information, after which the index file would be updated with the added new line indexes.

I have been developing this on both Linux and Windows, and on Windows the index file consisted partly of valid packed line numbers, and partly of bogus. Mixed. Why? I always failed to understand the reason for this. Now here it comes: I have opened the index file as a TEXT file, which works just fine on all Linux systems. But on Windows, bytes appearing as certain characters like "\n" might be magically transformed when written or read. For instance, if you write the line break byte "\n", Perl on Windows automagically transforms it into a Windows line break, which is 2 bytes large, "\r\n". Now that makes one of those index data elements 5 bytes large which breaks the alignment! At some point, 4 such shifts will have occurred, triggered by special bytes, pushing the alignment back into the correct one, which explains why later in the file there were valid numbers appearing again, just in the wrong position (shifted by 4×4 bytes).

It took me MONTHS to locate and understand that problem, hey I’m no programmer! Thank god there is a function called binmode() that you can call on a file handler/descriptor with an additional argument to force Perl into reading and writing only raw bytes from/to a file. Like:

open(FH, "<", $filename);
binmode(FH, ":raw");

Now finally, my index file got read and written correctly. Note that stuff like this can also happen on non-UTF-8 Linux systems running Perl 5.6.x, but most prominently this happens on Win32, even with Perl 5.14.x+. When Perl uses Win32 APIs for text mode file access, it’s trying to be a little bit too smart. Which is ok most of the time, unless you run into something like this with no idea what Perl is actually fucking up in the background.

So kids, remember: Whenever you’re handling a BINARY file, always call binmode() on your file handler right after opening your file! If you don’t do this, your code will puke on your screen if you try to port it from Linux to Windows or if you just don’t know about this stuff, like me. It most likely WILL corrupt whatever binary data you’re handling if you don’t do this!

If you want to know how to build a binary index for fast low-memory seeking in huge text files (millions of lines) in Perl, please [check this out]. Just don’t forget to add binmode() when you take that code! Preferrably with the ":raw" argument!