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• Things I Have Learned About Emscripten

  1er septembre 2015, par Multimedia Mike — Cirrus Retro

  3 years ago, I released my Game Music Appreciation project, a website with a ludicrously uninspired title which allowed users a relatively frictionless method to experience a range of specialized music files related to old video games. However, the site required use of a special Chrome plugin. Ever since that initial release, my #1 most requested feature has been for a pure JavaScript version of the music player.

  “Impossible !” I exclaimed. “There’s no way JS could ever run fast enough to run these CPU emulators and audio synthesizers in real time, and allow for the visualization that I demand !” Well, I’m pleased to report that I have proved me wrong. I recently quietly launched a new site with what I hope is a catchier title, meant to evoke a cloud-based retro-music-as-a-service product : Cirrus Retro. Right now, it’s basically the same as the old site, but without the wonky Chrome-specific technology.

  Along the way, I’ve learned a few things about using Emscripten that I thought might be useful to share with other people who wish to embark on a similar journey. This is geared more towards someone who has a stronger low-level background (such as C/C++) vs. high-level (like JavaScript).

  General Goals
  Do you want to cross-compile an entire desktop application, one that relies on an extensive GUI toolkit ? That might be difficult (though I believe there is a path for porting qt code directly with Emscripten). Your better wager might be to abstract out the core logic and processes of the program and then create a new web UI to access them.

  Do you want to compile a game that basically just paints stuff to a 2D canvas ? You’re in luck ! Emscripten has a porting path for SDL. Make a version of your C/C++ software that targets SDL (generally not a tall order) and then compile that with Emscripten.

  Do you just want to cross-compile some functionality that lives in a library ? That’s what I’ve done with the Cirrus Retro project. For this, plan to compile the library into a JS file that exports some public functions that other, higher-level, native JS (i.e., JS written by a human and not a computer) will invoke.

  Memory Levels
  When porting C/C++ software to JavaScript using Emscripten, you have to think on 2 different levels. Or perhaps you need to force JavaScript into a low level C lens, especially if you want to write native JS code that will interact with Emscripten-compiled code. This often means somehow allocating chunks of memory via JS and passing them to the Emscripten-compiled functions. And you wouldn’t believe the type of gymnastics you need to execute to get native JS and Emscripten-compiled JS to cooperate.
  

  “Emscripten : Pointers and Pointers” is the best (and, really, ONLY) explanation I could find for understanding the basic mechanics of this process, at least when I started this journey. However, there’s a mistake in the explanation that left me confused for a little while, and I’m at a loss to contact the author (doesn’t anyone post a simple email address anymore ?).

  Per the best of my understanding, Emscripten allocates a large JS array and calls that the memory space that the compiled C/C++ code is allowed to operate in. A pointer in C/C++ code will just be an index into that mighty array. Really, that’s not too far off from how a low-level program process is supposed to view memory– as a flat array.

  Eventually, I just learned to cargo-cult my way through the memory allocation process. Here’s the JS code for allocating an Emscripten-compatible byte buffer, taken from my test harness (more on that later) :

  var musicBuffer = fs.readFileSync(testSpec[’filename’]) ;
  var musicBufferBytes = new Uint8Array(musicBuffer) ;
  var bytesMalloc = player._malloc(musicBufferBytes.length) ;
  var bytes = new Uint8Array(player.HEAPU8.buffer, bytesMalloc, musicBufferBytes.length) ;
  bytes.set(new Uint8Array(musicBufferBytes.buffer)) ;
  

  So, read the array of bytes from some input source, create a Uint8Array from the bytes, use the Emscripten _malloc() function to allocate enough bytes from the Emscripten memory array for the input bytes, then create a new array… then copy the bytes…

  You know what ? It’s late and I can’t remember how it works exactly, but it does. It has been a few months since I touched that code (been fighting with front-end website tech since then). You write that memory allocation code enough times and it begins to make sense, and then you hope you don’t have to write it too many more times.

  Multithreading
  You can’t port multithreaded code to JS via Emscripten. JavaScript has no notion of threads ! If you don’t understand the computer science behind this limitation, a more thorough explanation is beyond the scope of this post. But trust me, I’ve thought about it a lot. In fact, the official Emscripten literature states that you should be able to port most any C/C++ code as long as 1) none of the code is proprietary (i.e., all the raw source is available) ; and 2) there are no threads.

  Yes, I read about the experimental pthreads support added to Emscripten recently. Don’t get too excited ; that won’t be ready and widespread for a long time to come as it relies on a new browser API. In the meantime, figure out how to make your multithreaded C/C++ code run in a single thread if you want it to run in a browser.

  Printing Facility
  Eventually, getting software to work boils down to debugging, and the most primitive tool in many a programmer’s toolbox is the humble print statement. A print statement allows you to inspect a piece of a program’s state at key junctures. Eventually, when you try to cross-compile C/C++ code to JS using Emscripten, something is not going to work correctly in the generated JS “object code” and you need to understand what. You’ll be pleading for a method of just inspecting one variable deep in the original C/C++ code.

  I came up with this simple printf-workalike called emprintf() :

  #ifndef EMPRINTF_H
  #define EMPRINTF_H
  #include <stdio .h>
  
  #include <stdarg .h>
  
  #include <emscripten .h>
  #define MAX_MSG_LEN 1000
  /* NOTE : Don’t pass format strings that contain single quote (’) or newline
  
  * characters. */
  
  static void emprintf(const char *format, ...)
  
  
  
      char msg[MAX_MSG_LEN] ;
  
      char consoleMsg[MAX_MSG_LEN + 16] ;
  
      va_list args ;
  
      /* create the string */
  
      va_start(args, format) ;
  
      vsnprintf(msg, MAX_MSG_LEN, format, args) ;
  
      va_end(args) ;
      /* wrap the string in a console.log(’’) statement */
  
      snprintf(consoleMsg, MAX_MSG_LEN + 16, "console.log(’%s’)", msg) ;
      /* send the final string to the JavaScript console */
  
      emscripten_run_script(consoleMsg) ;
  
  
  #endif  /* EMPRINTF_H */
  

  Put it in a file called “emprint.h”. Include it into any C/C++ file where you need debugging visibility, use emprintf() as a replacement for printf() and the output will magically show up on the browser’s JavaScript debug console. Heed the comments and don’t put any single quotes or newlines in strings, and keep it under 1000 characters. I didn’t say it was perfect, but it has helped me a lot in my Emscripten adventures.

  Optimization Levels
  Remember to turn on optimization when compiling. I have empirically found that optimizing for size (-Os) leads to the best performance all around, in addition to having the smallest size. Just be sure to specify some optimization level. If you don’t, the default is -O0 which offers horrible performance when running in JS.

  Static Compression For HTTP Delivery
  JavaScript code compresses pretty efficiently, even after it has been optimized for size using -Os. I routinely see compression ratios between 3.5:1 and 5:1 using gzip.

  Web servers in this day and age are supposed to be smart enough to detect when a requesting web browser can accept gzip-compressed data and do the compression on the fly. They’re even supposed to be smart enough to cache compressed output so the same content is not recompressed for each request. I would have to set up a series of tests to establish whether either of the foregoing assertions are correct and I can’t be bothered. Instead, I took it into my own hands. The trick is to pre-compress the JS files and then instruct the webserver to serve these files with a ‘Content-Type’ of ‘application/javascript’ and a ‘Content-Encoding’ of ‘gzip’.

  1. Compress your large Emscripten-build JS files with ‘gzip’ : ‘gzip compiled-code.js’
  2. Rename them from extension .js.gz to .jsgz
  3. Tell the webserver to deliver .jsgz files with the correct Content-Type and Content-Encoding headers

  To do that last step with Apache, specify these lines :

  AddType application/javascript jsgz
  AddEncoding gzip jsgz
  

  They belong in either a directory’s .htaccess file or in the sitewide configuration (/etc/apache2/mods-available/mime.conf works on my setup).

  Build System and Build Time Optimization
  Oh goodie, build systems ! I had a very specific manner in which I wanted to build my JS modules using Emscripten. Can I possibly coerce any of the many popular build systems to do this ? It has been a few months since I worked on this problem specifically but I seem to recall that the build systems I tried to used would freak out at the prospect of compiling stuff to a final binary target of .js.

  I had high hopes for Bazel, which Google released while I was developing Cirrus Retro. Surely, this is software that has been battle-tested in the harshest conditions of one of the most prominent software-developing companies in the world, needing to take into account the most bizarre corner cases and still build efficiently and correctly every time. And I have little doubt that it fulfills the order. Similarly, I’m confident that Google also has a team of no fewer than 100 or so people dedicated to developing and supporting the project within the organization. When you only have, at best, 1-2 hours per night to work on projects like this, you prefer not to fight with such cutting edge technology and after losing 2 or 3 nights trying to make a go of Bazel, I eventually put it aside.

  I also tried to use Autotools. It failed horribly for me, mostly for my own carelessness and lack of early-project source control.

  After that, it was strictly vanilla makefiles with no real dependency management. But you know what helps in these cases ? ccache ! Or at least, it would if it didn’t fail with Emscripten.

  Quick tip : ccache has trouble with LLVM unless you set the CCACHE_CPP2 environment variable (e.g. : “export CCACHE_CPP2=1”). I don’t remember the specifics, but it magically fixes things. Then, the lazy build process becomes “make clean && make”.

  Testing
  If you have never used Node.js, testing Emscripten-compiled JS code might be a good opportunity to start. I was able to use Node.js to great effect for testing the individually-compiled music player modules, wiring up a series of invocations using Python for a broader test suite (wouldn’t want to go too deep down the JS rabbit hole, after all).

  Be advised that Node.js doesn’t enjoy the same kind of JIT optimizations that the browser engines leverage. Thus, in the case of time critical code like, say, an audio synthesis library, the code might not run in real time. But as long as it produces the correct bitwise waveform, that’s good enough for continuous integration.

  Also, if you have largely been a low-level programmer for your whole career and are generally unfamiliar with the world of single-threaded, event-driven, callback-oriented programming, you might be in for a bit of a shock. When I wanted to learn how to read the contents of a file in Node.js, this is the first tutorial I found on the matter. I thought the code presented was a parody of bad coding style :

  var fs = require("fs") ;
  var fileName = "foo.txt" ;
  fs.exists(fileName, function(exists) 
  
    if (exists) 
  
      fs.stat(fileName, function(error, stats) 
  
        fs.open(fileName, "r", function(error, fd) 
  
          var buffer = new Buffer(stats.size) ;
  
          fs.read(fd, buffer, 0, buffer.length, null, function(error, bytesRead, buffer) 
  
            var data = buffer.toString("utf8", 0, buffer.length) ;
  
            console.log(data) ;
  
            fs.close(fd) ;
  
          ) ;
  
        ) ;
  
      ) ;
  
    ) ;
  

  Apparently, this kind of thing doesn’t raise an eyebrow in the JS world.

  Now, I understand and respect the JS programming model. But this was seriously frustrating when I first encountered it because a simple script like the one I was trying to write just has an ordered list of tasks to complete. When it asks for bytes from a file, it really has nothing better to do than to wait for the answer.

  Thankfully, it turns out that Node’s fs module includes synchronous versions of the various file access functions. So it’s all good.

  Conclusion
  I’m sure I missed or underexplained some things. But if other brave souls are interested in dipping their toes in the waters of Emscripten, I hope these tips will come in handy.

  The post Things I Have Learned About Emscripten first appeared on Breaking Eggs And Making Omelettes.

• Saying Goodbye To Old Machines

  1er décembre 2014, par Multimedia Mike — General, powerpc, via

  I recently sent a few old machines off for recycling. Both had relevance to the early days of the FATE testing effort. As is my custom, I photographed them (poorly, of course).

  First, there’s the PowerPC-based Mac Mini I procured thanks to a Craigslist ad in late 2006. I had plans to develop automated FFmpeg building and testing and was already looking ahead toward testing multiple CPU architectures. Again, this was 2006 and PowerPC wasn’t completely on the outs yet– although Apple’s MacTel transition was in full swing, the entire new generation of video game consoles was based on PowerPC.

  
  

  

  Click for larger image

  
  

  I remember trying to find a Mac Mini PPC on Craigslist. Many were to be found, but all asked more than the price of even a new Mac Mini Intel, always because the seller was leaving all of last year’s applications and perhaps including a monitor, neither of which I needed. Fortunately, I found this bare Mac Mini. Also fortunate was the fact that it was far easier to install Linux on it than the first PowerPC machine I owned.

  After FATE operation transitioned away from me, I still kept the machine in service as an edge server and automated backup machine. That is, until the hard drive failed on reboot one day. Thus, when it was finally time to recycle the computer, I felt it necessary to disassemble the machine and remove the hard drive for possible salvage and then for destruction.
  

  If you’ve ever attempted to upgrade or otherwise service this style of Mac Mini, you will no doubt recognize the pictured paint scraper tool as standard kit. I have had that tool since I first endeavored to upgrade the RAM to 1 GB from the standard 1/2 GB. Performing such activities on a Mac Mini is tedious, but only if you care about putting it back together afterwards.

  The next machine is a bit older. I put it together nearly a decade ago, early in 2005. This machine’s original duty was “download agent”– this would be more specifically called a BitTorrent machine in modern tech parlance. Back then, I placed it on someone else’s woefully underutilized home broadband connection (with their permission, of course) when I was too cheap to upgrade from dialup.

  
  

  

  Click for larger image

  
  

  This is a small form factor system from VIA that was clearly designed with home theater PC (HTPC) use cases in mind. It has a VIA C3 x86-compatible CPU (according to my notes, Centaur VIA Samuel 2 stepping 03, flags : fpu de tsc msr cx8 mtrr pge mmx 3dnow) and 128 MB of RAM (initially ; I upgraded it to 512 MB some years later, just for the sake of doing it). And then there was the 120 GB PATA HD for all that downloaded goodness.

  
  

  

  Click for larger image

  
  

  I have specific memories of a time when my main computer at home wasn’t working correctly for one reason or another. Instead, I logged into this machine remotely via SSH to make several optimizations and fixes on FFmpeg’s VP3/Theora video decoder, all from the terminal, without being able to see the decoded images with my own eyes (which is why I insist that even blind people could work on video codecs).

  By the time I got my own broadband, I had become inspired to attempt the automated build and test system for FFmpeg. This was the machine I used for prototyping early brainstorms of FATE. By the time I put a basic build/test system into place in early 2008, I had much faster computers that could build and test the project– obvious limitation of this machine is that it could take at least 1/2 hour to build the entire codebase, and that was the project from 8 years ago.

  So the machine got stuffed in a closet somewhere along the line. The next time I pulled it out was in 2010 when I wanted to toy with Dreamcast programming once more (the machine appears in one of the photos in this post). This was the only machine I still owned which still had an RS-232 serial port (I didn’t know much about USB serial converters yet), plus it still had a bunch of pre-compiled DC homebrew binaries (I was having trouble getting the toolchain to work right).

  The next time I dusted off this machine was late last year when I was trying some experiments with the Microsoft Xbox’s IDE drive (a photo in that post also shows the machine ; this thing shows up a lot on this blog). The VIA machine was the only machine I still owned which had 40-pin IDE connectors which was crucial to my experiment.

  At this point, I was trying to make the machine more useful which meant replacing the ancient Gentoo Linux distribution as well as simply interacting with it via a keyboard and mouse. I have a long Evernote entry documenting a comedy of errors revolving around this little box. The interaction troubles were due to the fact that I didn’t have any PS/2 keyboards left and I couldn’t make a USB keyboard work with it. Diego was able to explain that I needed to flip a bit in the BIOS to address this which worked. As for upgrading the OS, I tried numerous Linux distributions large and small, mostly focusing on the small. None worked. I eventually learned that, while I was trying to use i686 distributions, this machine did not actually qualify as an i686 CPU ; installations usually booted but failed because the default kernel required the cmov instruction. I was advised to try i386 distros instead. My notes don’t indicate whether I had any luck on this front before I gave up and moved on.

  I just made the connection that this VIA machine has two 40-pin IDE connectors which means that the thing was technically capable of supporting up to 4 IDE devices. Obviously, the computer couldn’t really accommodate that in terms of space or power. When I wanted to try installing a new OS, I needed take off the top and connect a rather bulky IDE CD-ROM drive. This computer’s casing was supposed to be able to support a slimline optical drive (perhaps like the type found in laptops), but I could never quite visualize how that was supposed to work, space-wise. When I disassembled the PowerPC Mac Mini, I realized I might be able to repurpose that machines optical drive for this computer. Obviously, I thought better of trying since both machines are off to the recycle pile.

  I would still like to work on the Xbox project a bit more, but I procured a different, unused, much more powerful yet still old computer that has a motherboard with 1 PATA connector in addition to 6 SATA connectors. If I ever get around to toying with Linux kernel development, this should be a much more appropriate platform to use.

  I thought about turning this machine into an old Windows XP (and lower, down to Windows 3.1) gaming platform ; the capabilities of the machine would probably be perfect for a huge portion of my Windows game collection. But I think the lack of an optical drive renders this idea intractable. External USB drives are likely out of the question since there is very little chance that this motherboard featured USB 2.0 (the specs don’t mention 2.0, so the USB ports are probably 1.1).

  So it is with fond memories that I send off both machines, sans hard drives, to the recycle pile. I’m still deciding on an appropriate course of action for failed hard drives, though.

• Audio HLS with metadata on Mac from directory of mp3 files ?

  2 février 2017, par eagspoo

  I’m trying to create HLS output (m3u8 file + many .ts files) from a list of mp3 files where the mp3 id3 metadata is preserved in the HLS output.

  I’ve been trying ffmpeg like this :

  ffmpeg -f concat -i list.txt -hls_init_time 2 -hls_time 2 out.m3u8

  where list.txt contains :

  file 01.mp3
  
  file 02.mp3
  
  file 03.mp3
  
  file 04.mp3
  
  file 05.mp3
  
  file 06.mp3
  
  file 07.mp3
  
  file 08.mp3
  
  file 09.mp3
  
  file 10.mp3

  The result is a single out.m3u8 file and a single very large out0.ts file. I was expecting about 1500 ts files and an m3u8 file that contains the last 5 ts files.

  I’m completely new to ffmpeg and honestly I don’t want to learn it in depth right now.

  Does anyone know how to do this either with ffmpeg or otherwise ?

  ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libavresample   3.  1.  0 /  3.  1.  0
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, concat, from 'list.txt':
  
    Duration: N/A, start: -0.025056, bitrate: 238 kb/s
  
      Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 238 kb/s
  
      Metadata:
  
        encoder         : LAME3.99r
  
      Stream #0:1: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 700x700 [SAR 72:72 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
  
      Metadata:
  
        title           : cover
  
        comment         : Cover (front)
  
  [hls @ 0x7fc50f01aa00] Frame rate very high for a muxer not efficiently supporting it.
  
  Please consider specifying a lower framerate, a different muxer or -vsync 2
  
  No pixel format specified, yuvj444p for H.264 encoding chosen.
  
  Use -pix_fmt yuv420p for compatibility with outdated media players.
  
  [libx264 @ 0x7fc50f00dc00] using SAR=1/1
  
  [libx264 @ 0x7fc50f00dc00] MB rate (174240000) > level limit (2073600)
  
  [libx264 @ 0x7fc50f00dc00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7fc50f00dc00] profile High 4:4:4 Predictive, level 5.2, 4:4:4 8-bit
  
  Output #0, hls, to 'out.m3u8':
  
    Metadata:
  
      encoder         : Lavf57.56.100
  
      Stream #0:0: Video: h264 (libx264), yuvj444p(pc), 700x700 [SAR 72:72 DAR 1:1], q=-1--1, 90k fps, 90k tbn, 90k tbc
  
      Metadata:
  
        title           : cover
  
        comment         : Cover (front)
  
        encoder         : Lavc57.64.101 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1: Audio: aac (LC), 44100 Hz, stereo, fltp, 128 kb/s
  
      Metadata:
  
        encoder         : Lavc57.64.101 aac
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (mjpeg (native) -> h264 (libx264))
  
    Stream #0:0 -> #0:1 (mp3 (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame= 2256 fps=389 q=33.0 size=N/A time=00:00:00.02 bitrate=N/A dup=2255 drop=0 speed=0.00422x    
  
  frame= 2256 fps=358 q=33.0 size=N/A time=00:00:08.98 bitrate=N/A dup=2255 drop=0 speed=1.43x    
  
  frame= 2256 fps=332 q=33.0 size=N/A time=00:00:26.75 bitrate=N/A dup=2255 drop=0 speed=3.94x    
  
  frame= 2256 fps=309 q=33.0 size=N/A time=00:00:49.64 bitrate=N/A dup=2255 drop=0 speed=6.81x    
  
  frame= 2256 fps=289 q=33.0 size=N/A time=00:01:14.39 bitrate=N/A dup=2255 drop=0 speed=9.54x    
  
  frame= 2256 fps=272 q=33.0 size=N/A time=00:01:38.77 bitrate=N/A dup=2255 drop=0 speed=11.9x    
  
  frame= 2257 fps=257 q=33.0 size=N/A time=00:01:58.98 bitrate=N/A dup=2255 drop=0 speed=13.5x    
  
  frame= 2257 fps=243 q=33.0 size=N/A time=00:02:19.02 bitrate=N/A dup=2255 drop=0 speed=  15x    
  
  frame= 2257 fps=230 q=33.0 size=N/A time=00:02:38.64 bitrate=N/A dup=2255 drop=0 speed=16.2x    
  
  frame= 2257 fps=219 q=33.0 size=N/A time=00:03:00.61 bitrate=N/A dup=2255 drop=0 speed=17.5x    
  
  frame= 2257 fps=209 q=33.0 size=N/A time=00:03:20.81 bitrate=N/A dup=2255 drop=0 speed=18.6x    
  
  frame= 2257 fps=200 q=33.0 size=N/A time=00:03:44.28 bitrate=N/A dup=2255 drop=0 speed=19.9x    
  
  frame= 2257 fps=191 q=33.0 size=N/A time=00:04:06.90 bitrate=N/A dup=2255 drop=0 speed=20.9x    
  
  frame= 2257 fps=184 q=33.0 size=N/A time=00:04:30.33 bitrate=N/A dup=2255 drop=0 speed=  22x    
  
  frame= 2257 fps=176 q=33.0 size=N/A time=00:04:53.57 bitrate=N/A dup=2255 drop=0 speed=22.9x    
  
  frame= 2258 fps=170 q=33.0 size=N/A time=00:05:07.95 bitrate=N/A dup=2255 drop=0 speed=23.2x    
  
  frame= 2258 fps=164 q=33.0 size=N/A time=00:05:20.44 bitrate=N/A dup=2255 drop=0 speed=23.2x    
  
  frame= 2258 fps=158 q=33.0 size=N/A time=00:05:33.79 bitrate=N/A dup=2255 drop=0 speed=23.3x    
  
  frame= 2258 fps=153 q=33.0 size=N/A time=00:05:46.77 bitrate=N/A dup=2255 drop=0 speed=23.4x    
  
  frame= 2258 fps=148 q=33.0 size=N/A time=00:05:59.87 bitrate=N/A dup=2255 drop=0 speed=23.5x    
  
  frame= 2258 fps=143 q=33.0 size=N/A time=00:06:14.54 bitrate=N/A dup=2255 drop=0 speed=23.7x    
  
  frame= 2258 fps=138 q=33.0 size=N/A time=00:06:28.27 bitrate=N/A dup=2255 drop=0 speed=23.8x    
  
  frame= 2258 fps=134 q=33.0 size=N/A time=00:06:42.92 bitrate=N/A dup=2255 drop=0 speed=  24x    
  
  frame= 2258 fps=130 q=33.0 size=N/A time=00:06:56.57 bitrate=N/A dup=2255 drop=0 speed=24.1x    
  
  frame= 2258 fps=127 q=33.0 size=N/A time=00:07:10.16 bitrate=N/A dup=2255 drop=0 speed=24.2x    
  
  frame= 2258 fps=123 q=33.0 size=N/A time=00:07:25.04 bitrate=N/A dup=2255 drop=0 speed=24.3x    
  
  frame= 2258 fps=120 q=33.0 size=N/A time=00:07:39.41 bitrate=N/A dup=2255 drop=0 speed=24.4x    
  
  frame= 2258 fps=117 q=33.0 size=N/A time=00:07:55.57 bitrate=N/A dup=2255 drop=0 speed=24.6x    
  
  frame= 2258 fps=114 q=33.0 size=N/A time=00:08:12.64 bitrate=N/A dup=2255 drop=0 speed=24.9x    
  
  frame= 2258 fps=111 q=33.0 size=N/A time=00:08:30.24 bitrate=N/A dup=2255 drop=0 speed=25.1x    
  
  frame= 2259 fps=109 q=33.0 size=N/A time=00:08:46.00 bitrate=N/A dup=2255 drop=0 speed=25.3x    
  
  frame= 2259 fps=106 q=33.0 size=N/A time=00:09:03.14 bitrate=N/A dup=2255 drop=0 speed=25.5x    
  
  [aac @ 0x7fc50f00f400] Queue input is backward in time
  
  [hls @ 0x7fc50f01aa00] Non-monotonous DTS in output stream 0:1; previous: 49402501, current: 36948720; changing to 49402502. This may result in incorrect timestamps in the output file.
  
  
  
  ... about 25000 lines of this...
  
  
  
  frame= 2261 fps= 65 q=33.0 size=N/A time=00:09:08.93 bitrate=N/A dup=2255 drop=0 speed=15.8x    
  
  [hls @ 0x7fc50f01aa00] Non-monotonous DTS in output stream 0:1; previous: 49402502, current: 36950810; changing to 49402503. This may result in incorrect timestamps in the output file.
  
  [hls @ 0x7fc50f01aa00] Non-monotonous DTS in output stream 0:1; previous: 49408463, current: 49408084; changing to 49408464. This may result in incorrect timestamps in the output file.
  
  frame= 2261 fps= 59 q=33.0 size=N/A time=00:09:13.11 bitrate=N/A dup=2255 drop=0 speed=14.4x    
  
  frame= 2261 fps= 58 q=33.0 size=N/A time=00:09:30.15 bitrate=N/A dup=2255 drop=0 speed=14.7x    
  
  frame= 2262 fps= 57 q=33.0 size=N/A time=00:09:50.68 bitrate=N/A dup=2255 drop=0 speed=  15x    
  
  frame= 2262 fps= 57 q=33.0 size=N/A time=00:10:04.10 bitrate=N/A dup=2255 drop=0 speed=15.2x    
  
  frame= 2262 fps= 56 q=33.0 size=N/A time=00:10:20.52 bitrate=N/A dup=2255 drop=0 speed=15.4x    
  
  frame= 2262 fps= 55 q=33.0 size=N/A time=00:10:36.66 bitrate=N/A dup=2255 drop=0 speed=15.6x    
  
  frame= 2262 fps= 55 q=33.0 size=N/A time=00:10:52.31 bitrate=N/A dup=2255 drop=0 speed=15.8x    
  
  frame= 2262 fps= 54 q=33.0 size=N/A time=00:11:09.35 bitrate=N/A dup=2255 drop=0 speed=  16x    
  
  frame= 2262 fps= 53 q=33.0 size=N/A time=00:11:26.37 bitrate=N/A dup=2255 drop=0 speed=16.2x    
  
  frame= 2262 fps= 53 q=33.0 size=N/A time=00:11:43.44 bitrate=N/A dup=2255 drop=0 speed=16.4x    
  
  frame= 2262 fps= 52 q=33.0 size=N/A time=00:11:59.93 bitrate=N/A dup=2255 drop=0 speed=16.6x    
  
  frame= 2262 fps= 52 q=33.0 size=N/A time=00:12:15.48 bitrate=N/A dup=2255 drop=0 speed=16.8x    
  
  frame= 2262 fps= 51 q=33.0 size=N/A time=00:12:28.44 bitrate=N/A dup=2255 drop=0 speed=16.9x    
  
  frame= 2262 fps= 50 q=33.0 size=N/A time=00:12:43.93 bitrate=N/A dup=2255 drop=0 speed=  17x    
  
  frame= 2262 fps= 50 q=33.0 size=N/A time=00:12:59.30 bitrate=N/A dup=2255 drop=0 speed=17.2x    
  
  frame= 2263 fps= 49 q=33.0 size=N/A time=00:13:15.93 bitrate=N/A dup=2255 drop=0 speed=17.4x    
  
  frame= 2263 fps= 49 q=33.0 size=N/A time=00:13:41.70 bitrate=N/A dup=2255 drop=0 speed=17.7x    
  
  frame= 2263 fps= 48 q=33.0 size=N/A time=00:14:02.65 bitrate=N/A dup=2255 drop=0 speed=  18x    
  
  frame= 2263 fps= 48 q=33.0 size=N/A time=00:14:25.57 bitrate=N/A dup=2255 drop=0 speed=18.3x    
  
  frame= 2263 fps= 47 q=33.0 size=N/A time=00:14:49.34 bitrate=N/A dup=2255 drop=0 speed=18.6x    
  
  frame= 2263 fps= 47 q=33.0 size=N/A time=00:15:11.17 bitrate=N/A dup=2255 drop=0 speed=18.8x    
  
  frame= 2263 fps= 46 q=33.0 size=N/A time=00:15:31.60 bitrate=N/A dup=2255 drop=0 speed=19.1x    
  
  frame= 2263 fps= 46 q=33.0 size=N/A time=00:15:47.25 bitrate=N/A dup=2255 drop=0 speed=19.2x    
  
  frame= 2263 fps= 45 q=33.0 size=N/A time=00:16:03.30 bitrate=N/A dup=2255 drop=0 speed=19.3x    
  
  frame= 2263 fps= 45 q=33.0 size=N/A time=00:16:22.99 bitrate=N/A dup=2255 drop=0 speed=19.5x    
  
  frame= 2263 fps= 45 q=33.0 size=N/A time=00:16:45.12 bitrate=N/A dup=2255 drop=0 speed=19.8x    
  
  frame= 2264 fps= 44 q=33.0 size=N/A time=00:17:05.99 bitrate=N/A dup=2255 drop=0 speed=  20x    
  
  frame= 2264 fps= 44 q=33.0 size=N/A time=00:17:25.03 bitrate=N/A dup=2255 drop=0 speed=20.2x    
  
  frame= 2264 fps= 43 q=33.0 size=N/A time=00:17:43.12 bitrate=N/A dup=2255 drop=0 speed=20.3x    
  
  frame= 2264 fps= 43 q=33.0 size=N/A time=00:18:01.35 bitrate=N/A dup=2255 drop=0 speed=20.5x    
  
  frame= 2264 fps= 42 q=33.0 size=N/A time=00:18:17.79 bitrate=N/A dup=2255 drop=0 speed=20.6x    
  
  frame= 2264 fps= 42 q=33.0 size=N/A time=00:18:35.15 bitrate=N/A dup=2255 drop=0 speed=20.7x    
  
  frame= 2264 fps= 42 q=33.0 size=N/A time=00:18:55.82 bitrate=N/A dup=2255 drop=0 speed=20.9x    
  
  frame= 2264 fps= 41 q=33.0 size=N/A time=00:19:17.46 bitrate=N/A dup=2255 drop=0 speed=21.1x    
  
  frame= 2264 fps= 41 q=33.0 size=N/A time=00:19:28.37 bitrate=N/A dup=2255 drop=0 speed=21.1x    
  
  frame= 2264 fps= 41 q=33.0 size=N/A time=00:19:42.21 bitrate=N/A dup=2255 drop=0 speed=21.2x    
  
  frame= 2264 fps= 40 q=33.0 size=N/A time=00:20:03.11 bitrate=N/A dup=2255 drop=0 speed=21.3x    
  
  frame= 2264 fps= 40 q=33.0 size=N/A time=00:20:20.36 bitrate=N/A dup=2255 drop=0 speed=21.5x    
  
  frame= 2264 fps= 39 q=33.0 size=N/A time=00:20:38.57 bitrate=N/A dup=2255 drop=0 speed=21.6x    
  
  frame= 2265 fps= 39 q=33.0 size=N/A time=00:20:55.79 bitrate=N/A dup=2255 drop=0 speed=21.7x    
  
  frame= 2265 fps= 39 q=33.0 size=N/A time=00:21:13.81 bitrate=N/A dup=2255 drop=0 speed=21.8x    
  
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  frame= 2265 fps= 38 q=33.0 size=N/A time=00:21:41.53 bitrate=N/A dup=2255 drop=0 speed=21.9x    
  
  frame= 2265 fps= 38 q=33.0 size=N/A time=00:21:54.44 bitrate=N/A dup=2255 drop=0 speed=  22x    
  
  frame= 2265 fps= 38 q=33.0 size=N/A time=00:22:09.35 bitrate=N/A dup=2255 drop=0 speed=  22x    
  
  frame= 2265 fps= 37 q=33.0 size=N/A time=00:22:23.84 bitrate=N/A dup=2255 drop=0 speed=22.1x    
  
  frame= 2265 fps= 37 q=33.0 size=N/A time=00:22:40.98 bitrate=N/A dup=2255 drop=0 speed=22.2x    
  
  frame= 2265 fps= 37 q=33.0 size=N/A time=00:22:59.99 bitrate=N/A dup=2255 drop=0 speed=22.3x    
  
  frame= 2265 fps= 36 q=33.0 size=N/A time=00:23:21.29 bitrate=N/A dup=2255 drop=0 speed=22.5x    
  
  frame= 2265 fps= 36 q=33.0 size=N/A time=00:23:37.96 bitrate=N/A dup=2255 drop=0 speed=22.6x    
  
  frame= 2265 fps= 36 q=33.0 size=N/A time=00:23:53.49 bitrate=N/A dup=2255 drop=0 speed=22.6x    
  
  frame= 2265 fps= 35 q=33.0 size=N/A time=00:24:10.42 bitrate=N/A dup=2255 drop=0 speed=22.7x    
  
  frame= 2265 fps= 35 q=33.0 size=N/A time=00:24:29.64 bitrate=N/A dup=2255 drop=0 speed=22.8x    
  
  frame= 2265 fps= 35 q=33.0 size=N/A time=00:24:52.61 bitrate=N/A dup=2255 drop=0 speed=  23x    
  
  frame= 2265 fps= 35 q=-1.0 Lsize=N/A time=00:25:02.45 bitrate=N/A dup=2255 drop=0 speed=  23x    
  
  video:1482kB audio:33826kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  [libx264 @ 0x7fc50f00dc00] frame I:10    Avg QP:21.37  size:145718
  
  [libx264 @ 0x7fc50f00dc00] frame P:571   Avg QP:21.23  size:    31
  
  [libx264 @ 0x7fc50f00dc00] frame B:1684  Avg QP:30.33  size:    25
  
  [libx264 @ 0x7fc50f00dc00] consecutive B-frames:  0.8%  0.1%  0.0% 99.1%
  
  [libx264 @ 0x7fc50f00dc00] mb I  I16..4:  0.0% 98.3%  1.7%
  
  [libx264 @ 0x7fc50f00dc00] mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip:100.0%
  
  [libx264 @ 0x7fc50f00dc00] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.0%  0.0%  0.0%  direct: 0.0%  skip:100.0%  L0: 0.0% L1:100.0% BI: 0.0%
  
  [libx264 @ 0x7fc50f00dc00] 8x8 transform intra:98.3% inter:100.0%
  
  [libx264 @ 0x7fc50f00dc00] coded y,u,v intra: 100.0% 70.2% 62.8% inter: 0.0% 0.0% 0.0%
  
  [libx264 @ 0x7fc50f00dc00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 18% 39%  5%  4%  4%  6%  6% 10%
  
  [libx264 @ 0x7fc50f00dc00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 12% 15%  9%  8% 10%  9%  9% 11%
  
  [libx264 @ 0x7fc50f00dc00] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x7fc50f00dc00] ref P L0: 11.6% 79.1%  9.3%
  
  [libx264 @ 0x7fc50f00dc00] ref B L1: 50.0% 50.0%
  
  [libx264 @ 0x7fc50f00dc00] kb/s:482409.22
  
  [aac @ 0x7fc50f00f400] Qavg: 491.256