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• JavaCV Create Compatible MP4

  15 juin 2017, par Hamish258

  Trying to modify JavaCV 3.2.0 sample https://github.com/bytedeco/javacv/blob/master/samples/WebcamAndMicrophoneCapture.java, to produce an mp4 that quicktime on macOS 10.12.5 can use. Output mp4 works fine with VLC but for the software I’m producing I’d like to minimise users having to install additional products.

  The sample code produces the following output

  [libx264 @ 0x7f927794e200] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x7f927794e200] profile Constrained Baseline, level 3.1
[libx264 @ 0x7f927794e200] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=4 lookahead_threads=4 sliced_threads=1 slices=4 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=60 keyint_min=6 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=28.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, mp4, to 'alatest.mp4':
 Metadata:
   encoder         : Lavf57.56.100
   Stream #0:0: Video: h264 (Constrained Baseline) ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q=2-31, 2000 kb/s, 15360 tbn
   Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo fltp, 192 kb/s

  The constrained baseline to 3.1 should produce usable mp4 according to https://trac.ffmpeg.org/wiki/Encode/H.264

  If I use the command line ffmpeg -i alatest.mp4 -pix_fmt yuv420p alantest.mp4 it produces a usable mo4, even though as you can see above yuv420p is the pixel format in use so there’s something else I don’t understand, the code snippet from the sample link is :

     FFmpegFrameRecorder recorder = new FFmpegFrameRecorder("alatest.mp4",1280, 720, 2);
   recorder.setInterleaved(true);
   recorder.setVideoOption("tune", "zerolatency");
   recorder.setVideoOption("preset", "ultrafast");
   recorder.setVideoOption("crf", "28");
   recorder.setVideoBitrate(2000000);
   recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
   recorder.setPixelFormat(avutil.AV_PIX_FMT_YUV420P);
   recorder.setFormat("flv");
   recorder.setFrameRate(30);
   recorder.setGopSize(60);

  The command line ffmpeg is displaying

  [libx264 @ 0x7ffca4019400] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x7ffca4019400] profile High, level 3.1
[libx264 @ 0x7ffca4019400] 264 - core 148 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 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=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=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=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'alantest.mp4':
 Metadata:
   encoder         : Lavf57.71.100
   Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q=-1--1, 30 fps, 15360 tbn, 30 tbc
   Metadata:
     encoder         : Lavc57.89.100 libx264
   Side data:
     cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
   Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s
   Metadata:
     encoder         : Lavc57.89.100 aac
frame=  179 fps= 54 q=-1.0 Lsize=     570kB time=00:00:05.94 bitrate= 786.2kbits/s dup=93 drop=0 speed= 1.8x
video:470kB audio:93kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.341890%

  This is using a High profile and I see q being set differently and tbc. I can’t figure out how to mimic this behaviour in JavaCV, all help greatly appreciated !

• linking against SDL library on ubuntu

  18 novembre 2013, par ali129

  this is my first post
  I have this problem with SDL library and "ffmpeg's ffplay" and "dosbox" on ubuntu. Here is what happenning :
  I have installed SDL and code::blocks.
  I also wrote a simple sdl program that shows a picture and tried to compile it tree ways :

  1- On command prompt which compiled and works perfectly. ( i mean : gcc -o hellosdl hellosd.c -lsdlmain -lsdl)

  2- On code::blocks by choosing file->new->project->SDL project
  which compiled but gives an error regarding i can't initialize graphic

  and finally
  3- On code::blocks but this time i manually configured sdl. i mean i simply choosed a blanked c file.then added sdl linker options "-lsdlmain and -lsdl" in code::blocks linker settings. and this time the program workes perfectly.

  Now the problem i have with dosbox and ffmpeg. I tried to compile these programs by running ./configure and make and they compiled without any error. but when i try to run dosbox or ffplay they give me these errors :

  ffplay error :
  ffplay version 0.11.1.git Copyright (c) 2003-2012 the FFmpeg developers
  built on Oct 15 2013 04:34:36 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
  configuration :
  libavutil 51. 73.101 / 51. 73.101
  libavcodec 54. 56.100 / 54. 56.100
  libavformat 54. 27.101 / 54. 27.101
  libavdevice 54. 2.100 / 54. 2.100
  libavfilter 3. 16.104 / 3. 16.104
  libswscale 2. 1.101 / 2. 1.101
  libswresample 0. 15.100 / 0. 15.100
  Could not initialize SDL - No available video device
  (Did you set the DISPLAY variable ?)

  and yes my DISPLAY variable is set correctly

  echo $DISPLAY
  :0.0

  and

  dosbox error :

  ---

  Exit to error : Can't init SDL No available video device

  i also tried installing dosbox using sudo apt-get install dosbox and it works perfectly.

  i don't know why for some occasion my sdl library works and for some doesn't .
  it would be great if you could help me.

• Launch Leech and the History of WMV

  14 septembre 2010, par Multimedia Mike — General

  I was combing through my programming archives again and came across an old Perl script called launch-leech.pl. This was a private script I used to maintain for the benefit of myself and a few friends. See, there was this site called Launch.com (URL doesn’t seem to do anything as of this writing but here’s the Wikipedia page). Purchased by Yahoo ! in 2001, Launch still maintained their independent branding. They also carried a lot of music videos, of which I am a huge junkie. launch-leech.pl was the tool I used to download the videos. This was particularly useful since I stubbornly clung to dialup internet access until mid-2004 and it would have been impossible to stream video at any decent quality (though there were 56k streams, so like I said– not possible at any decent quality).

  
  
  

  Technically
  I followed Launch.com for many years. To be honest, I only “followed” in that I figured out where their “latest videos” URL lived and regularly polled it. Each video had either a 6-, 7-, or 8-digit unique ID that could be plugged into the launch-leech.pl script which would then have a conversation with the relevant servers, determine the correct streaming URL with the highest quality, then download and save the URL by handing it off to an external program (first ASFRecorder, though I later switched to mmsclient).

  At one point, I even wrote a crawler that compiled an offline database of all the videos, their IDs and their metadata. I never thought of anything interesting to do with it, though.

  
  
  

  Windows Media Legacy
  During these glory days of leeching, Launch.com streamed using Windows Media. I admit, it’s a bit of a blur now — the site might have used Real or QuickTime, but I was obviously most in tune with the WM side. I remember when I first found the site circa 2000-2001, the videos were in MS MPEG-4v3, and the high quality bitrate was 300 kbits/sec. Eventually, Launch.com would stream WMV7, WMV8, and finally WMV9, with bitrates up to 700 kbits/sec. However, they never broke free of the 320×240 encoding resolution, which was frustrating. When I wasn’t able to notice any substantial difference between 300 and 700 kbits/sec, I felt it might be time to put those extra bits to work on a resolution upgrade.

  At least they were nice enough to re-encode a number of old videos using better codecs and bitrates with each revision, thus prompting me to scan through the site collecting updated video IDs for download.

  
  
  

  Epilogue
  I don’t clearly remember when I stopped visiting Launch.com. Video-wise, the web has been a blur of Flash video ever since about 2006. Meanwhile, I spent a lot of time collecting a bunch of music videos in the first half of the decade only to find that pretty much every version of every music video made since the dawn of time is available on demand thanks to YouTube. I have found that this phenomenon manifests in many areas as internet technology marches on.

  The Real Entertainment
  The launch-leech.pl tool represents a recurring pattern for me. I derive as much — if not more — entertainment from creating programs like launch-leech.pl (and implicitly reverse engineering something in the process ; in this case, a website) as I do from the intended entertainment media itself. I seem to have this issue a lot with games, too.

  Is this an issue for anyone else ? Am I the only one who would rather play with the box that a shiny toy comes packaged in ?