Recherche avancée

Sur d’autres sites (10156)

• ffplay playing videos very slow and choppy

  2 juin 2014, par Pavan K

  I am trying to compile ffplay from sources to run on pcduino running ubuntu

  If I install ffplay via sudo apt-get install ffmpeg the videos play perfectly But I tried to compile ffplay from the sources using the guide here ffmpeg compilation the videos play terribly slowand look very very choppy.

  Do I have to use some specific flags for compilation. I just would like a bare bones video player ffplay. I do not want to encode or do any heavy computation with the binary.

  ffplay verison is

      ./ffplay -version    
  
  ffplay version git-2013-06-14-d891d35
  
  built on Jun  2 2014 14:15:57 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
  
  configuration: --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
  
  libavutil      52. 35.101 / 52. 35.101
  
  libavcodec     55. 16.100 / 55. 16.100
  
  libavformat    55.  8.102 / 55.  8.102
  
  libavdevice    55.  2.100 / 55.  2.100
  
  libavfilter     3. 77.101 /  3. 77.101
  
  libswscale      2.  3.100 /  2.  3.100
  
  libswresample   0. 17.102 /  0. 17.102
  
  libpostproc    52.  3.100 / 52.  3.100

  And this is from apt-get

  ffplay -version 
  
  avplay version 0.8.10-4:0.8.10-0ubuntu0.12.04.1, Copyright (c) 2003-2013 the Libav developers
  
    built on Feb  6 2014 21:09:10 with gcc 4.6.3
  
  avplay 0.8.10-4:0.8.10-0ubuntu0.12.04.1
  
  libavutil    51. 22. 2 / 51. 22. 2
  
  libavcodec   53. 35. 0 / 53. 35. 0
  
  libavformat  53. 21. 1 / 53. 21. 1
  
  libavdevice  53.  2. 0 / 53.  2. 0
  
  libavfilter   2. 15. 0 /  2. 15. 0
  
  libswscale    2.  1. 0 /  2.  1. 0
  
  libpostproc  52.  0. 0 / 52.  0. 0

  i have the following error when I play with the built ffplay

  ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred  0B f=0/0
  
  ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred  0B f=0/0

• 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 !

• Produce waveform video from audio using FFMPEG

  27 avril 2017, par RhythmicDevil

  I am trying to create a waveform video from audio. My goal is to produce a video that looks something like this

  

  For my test I have an mp3 that plays a short clipped sound. There are 4 bars of 1/4 notes and 4 bars of 1/8 notes played at 120bpm. I am having some trouble coming up with the right combination of preprocessing and filtering to produce a video that looks like the image. The colors dont have to be exact, I am more concerned with the shape of the beats. I tried a couple of different approaches using showwaves and showspectrum. I cant quite wrap my head around why when using showwaves the beats go past so quickly, but using showspectrum produces a video where I can see each individual beat.

  ShowWaves

  ffmpeg -i beat_test.mp3 -filter_complex "[0:a]showwaves=s=1280x100:mode=cline:rate=25:scale=sqrt,format=yuv420p[v]" -map "[v]" -map 0:a output_wav.mp4

  This link will download the output of that command.

  ShowSpectrum

  ffmpeg -i beat_test.mp3 -filter_complex "[0:a]showspectrum=s=1280x100:mode=combined:color=intensity:saturation=5:slide=1:scale=cbrt,format=yuv420p[v]" -map "[v]" -an -map 0:a output_spec.mp4

  This link will download the output of that command.

  I posted the simple examples because I didn’t want to confuse the issue by adding all the variations I have tried.

  In practice I suppose I can get away with the output from showspectrum but I’d like to understand where/how I am thinking about this incorrectly. Thanks for any advice.

  Here is a link to the source audio file.