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• lavd : add xv output device

  14 mai 2013, par Stefano Sabatini

  lavd : add xv output device
  Based on the work of Jeff Moguillansky <Jeff.Moguillansky@am.sony.com>.
  See thread :
  
  Subject : [FFmpeg-devel] x11 output device for libavdevice
  
  Date : Wed, 10 Apr 2013 23:10:47 +0000
  

  • [DH] Changelog
  • [DH] configure
  • [DH] doc/outdevs.texi
  • [DH] libavdevice/Makefile
  • [DH] libavdevice/alldevices.c
  • [DH] libavdevice/version.h
  • [DH] libavdevice/xv.c

• FFMPEG avi to streaming mp4

  29 mai 2013, par Vprnl

  I'm trying to get ffmpeg to encode various AVI files to mp4 for streaming purposes but my inexperience with the subject matter is making me doubt I'll ever get this to work.

  I use this commandline :

  ffmpeg -i test.avi -vcodec libx264 -r 24 -ac 2 -acodec ac3 -ab 128k -bt 240k -preset    fast -strict -2 -b:v 320K -bufsize 62000 -maxrate 62000 -movflags frag_keyframe+empty_moov test.mp4

  I use the " -movflags frag_keyframe+empty_moov" to make it possible to serve a fragmented mp4

  And this is the log I get :

      file conversion error ffmpeg version N-53577-gced0307 Copyright (c) 2000-2013 the FFmpeg developers
  
        built on May 28 2013 12:21:54 with gcc 4.7.3 (GCC)
  
        configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0
  
      r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libil
  
      bc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus -
  
      -enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc
  
       --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
        libavutil      52. 34.100 / 52. 34.100
  
        libavcodec     55. 12.100 / 55. 12.100
  
        libavformat    55.  7.100 / 55.  7.100
  
        libavdevice    55.  1.101 / 55.  1.101
  
        libavfilter     3. 72.100 /  3. 72.100
  
        libswscale      2.  3.100 /  2.  3.100
  
        libswresample   0. 17.102 /  0. 17.102
  
        libpostproc    52.  3.100 / 52.  3.100
  
      [avi @ 002ce8c0] non-interleaved AVI
  
      Input #0, avi, from 'C:/temp/test.avi':
  
        Metadata:
  
          encoder         : MEncoder Sherpya-MT-SVN-r31027-4.2.5
  
        Duration: 01:15:15.47, start: 0.000000, bitrate: 4798 kb/s
  
          Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 23.98 tb
  
      n, 24k tbc
  
          Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side), fltp, 640 kb/s
  
      [libx264 @ 03c57020] max bitrate less than average bitrate, assuming CBR
  
      [libx264 @ 03c57020] using SAR=1/1
  
      [libx264 @ 03c57020] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
  
      [libx264 @ 03c57020] profile High, level 3.1
  
      [libx264 @ 03c57020] 264 - core 133 r2334 a3ac64b - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - op
  
      tions: cabac=1 ref=2 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=6 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
  
       8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlace
  
      d=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyi
  
      nt_min=24 scenecut=40 intra_refresh=0 rc_lookahead=30 rc=cbr mbtree=1 bitrate=320 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_m
  
      axrate=320 vbv_bufsize=62 nal_hrd=none ip_ratio=1.40 aq=1:1.00
  
      Output #0, mp4, to 'pipe:1':
  
        Metadata:
  
          encoder         : Lavf55.7.100
  
          Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 320 kb/s, 12288 tbn, 24
  
      tbc
  
          Stream #0:1: Audio: ac3 ([165][0][0][0] / 0x00A5), 48000 Hz, stereo, fltp, 128 kb/s
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (mpeg4 -> libx264)
  
        Stream #0:1 -> #0:1 (ac3 -> ac3)
  
      Press [q] to stop, [?] for help
  
      frame=   37 fps=0.0 q=0.0 size=       1kB time=00:00:01.97 bitrate=   4.7kbits/s
  
      frame=   41 fps= 36 q=27.0 size=       1kB time=00:00:01.97 bitrate=   4.7kbits/s
  
      frame=   51 fps= 31 q=22.0 size=       1kB time=00:00:02.49 bitrate=   3.7kbits/s
  
      frame=   63 fps= 27 q=21.0 size=       1kB time=00:00:02.97 bitrate=   3.1kbits/s
  
      frame=   82 fps= 29 q=21.0 size=       1kB time=00:00:03.48 bitrate=   2.7kbits/s
  
      frame=   91 fps= 26 q=21.0 size=       1kB time=00:00:03.99 bitrate=   2.3kbits/s
  
      frame=  101 fps= 25 q=23.0 size=       1kB time=00:00:04.47 bitrate=   2.1kbits/s
  
      frame=  114 fps= 25 q=21.0 size=       1kB time=00:00:04.98 bitrate=   1.9kbits/s
  
      frame=  128 fps= 25 q=26.0 size=       1kB time=00:00:05.46 bitrate=   1.7kbits/s
  
      frame=  135 fps= 24 q=38.0 size=       1kB time=00:00:05.97 bitrate=   1.6kbits/s
  
      frame=  141 fps= 23 q=45.0 size=       1kB time=00:00:05.97 bitrate=   1.6kbits/s

  I hope someone can point me in the right direction. The goal is to serve the file to a html5 player. But sadly that has not yet worked.
  Thanks !

  [EDIT]

  Sorry if I'm being unclear. I have two issues. First FFMPEG gives me an error (as you can see in the log) but I'm uncertain why I get this error and secondly, the stream does not actually work. The tanscoding starts, but the player never receives the video

• How To Play Hardware Accelerated Video on A Mac

  28 mai 2013, par Multimedia Mike — General

  I have a friend who was considering purchasing a Mac Mini recently. At the time of this writing, there are 3 desktop models (and 2 more “server” models).

  
  
  

  The cheapest one is a Core i5 2.5 GHz. Then there are 2 Core i7 models : 2.3 GHz and 2.6 GHz. The difference between the latter 2 is US$100. The only appreciable technical difference is the extra 0.3 GHz and the choice came down to those 2.

  He asked me which one would be able to play HD video at full frame rate. I found this query puzzling. But then, I have been “in the biz” for a bit too long. Whether or not a computer or device can play a video well depends on a lot of factors.

  Hardware Support
  First of all, looking at the raw speed of the general-purpose CPU inside of a computer as a gauge of video playback performance is generally misguided in this day and age. In general, we have a video standard (H.264, which I’ll focus on for this post) and many bits of hardware are able to accelerate decoding. So, the question is not whether the CPU can decode the data in real time, but can any other hardware in the device (likely the graphics hardware) handle it ? These machines have Intel HD 4000 graphics and, per my reading of the literature, they are capable of accelerating H.264 video decoding.

  Great, so the hardware supports accelerated decoding. So it’s a done deal, right ? Not quite…

  Operating System Support
  An application can’t do anything pertaining to hardware without permission from the operating system. So the next question is : Does Mac OS X allow an application to access accelerated video decoding hardware if it’s available ? This used to be a contentious matter (notably, Adobe Flash Player was unable to accelerate H.264 playback on Mac in the absence of such an API) but then Apple released an official API detailed in Technical Note TN2267.

  So, does this mean that video is magically accelerated ? Nope, we’re still not there yet…

  Application Support
  It’s great that all of these underlying pieces are in place, but if an individual application chooses to decode the video directly on the CPU, it’s all for naught. An application needs to query the facilities and direct data through the API if it wants to leverage the acceleration. Obviously, at this point it becomes a matter of “which application ?”

  My friend eventually opted to get the pricier of the desktop Mac Mini models and we ran some ad-hoc tests since I was curious how widespread the acceleration support is among Mac multimedia players. Here are some programs I wanted to test, playing 1080p H.264 :

  • Apple QuickTime Player
  • VLC
  • YouTube with Flash Player (any browser)
  • YouTube with Safari/HTML5
  • YouTube with Chrome/HTML5
  • YouTube with Firefox/HTML5
  • Netflix

  I didn’t take exhaustive notes but my impromptu tests revealed QuickTime Player was, far and away, the most performant player, occupying only around 5% of the CPU according to the Mac OS X System Profiler graph (which is likely largely spent on audio decoding).

  VLC consistently required 20-30% CPU, so it’s probably leveraging some acceleration facilities. I think that Flash Player and the various HTML5 elements performed similarly (their multi-process architectures can make such a trivial profiling test difficult).

  The outlier was Netflix running in Firefox via Microsoft’s Silverlight plugin. Of course, the inner workings of Netflix’s technology are opaque to outsiders and we don’t even know if it uses H.264. It may very well use Microsoft’s VC-1 which is not a capability provided by the Mac OS X acceleration API (it doesn’t look like the Intel HD 4000 chip can handle it either). I have never seen any data one way or another about how Netflix encodes video. However, I was able to see that Netflix required an enormous amount of CPU muscle on the Mac platform.

  Conclusion
  The foregoing is a slight simplification of the video playback pipeline. There are some other considerations, most notably how the video is displayed afterwards. To circle back around to the original question : Can the Mac Mini handle full HD video playback ? As my friend found, the meager Mac Mini can do an admirable job at playing full HD video without loading down the CPU.