Recherche avancée

Sur d’autres sites (8668)

• Streaming Webcam using VLC +FFmpeg over lan - Error : cannot pre fill buffer

  23 juin 2016, par user1804015

  I’ve been trying to stream my webcam over lan using VLC and FFmpeg

  but I end up with the error "Main stream error : cannot pre fill buffer"

  Here is the code I’ve tried

  ffmpeg -f x11grab -s 1680x1050 -r 30 -i :0.0+0,0 -vf "movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; [in] setpts=PTS-STARTPTS, [movie] overlay=main_w-overlay_w-10:main_h-overlay_h-10 [out]" -f alsa -ac 2 -i pulse -vcodec libx264 -preset ultrafast -s 1280x768 -acodec libfaac -threads 0 -f mpegts - | vlc -I dummy - --sout '#std{access=http,mux=ts,dst=thalha:3030}'

  And this is the output

  VLC media player 1.1.9 The Luggage (revision exported)
  
  FFmpeg version 0.6.6-4:0.6.6-0ubuntu0.11.04.1, Copyright (c) 2000-2010 the Libav developers
  
    built on Jun 12 2012 16:28:21 with gcc 4.5.2
  
    configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
  
    WARNING: library configuration mismatch
  
    libavutil   configuration: --extra-version=4:0.6.6-1ubuntu1+medibuntu1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libdirac --enable-libgsm --enable-libopenjpeg --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-version3 --enable-vaapi --enable-libopenjpeg --enable-libfaac --enable-nonfree --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libfaad --enable-libdirac --enable-libfaad --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavcodec  configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavformat configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavdevice configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavfilter configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libswscale  configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libpostproc configuration: --extra-version=4:0.6.6-0ubuntu0.11.04.1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --disable-stripping --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --shlibdir=/usr/lib/i686/cmov --cpu=i686 --enable-shared --disable-static --disable-ffmpeg --disable-ffplay
  
    libavutil     50.15. 1 / 50.15. 1
  
    libavcodec    52.72. 2 / 52.72. 2
  
    libavformat   52.64. 2 / 52.64. 2
  
    libavdevice   52. 2. 0 / 52. 2. 0
  
    libavfilter    1.19. 0 /  1.19. 0
  
    libswscale     0.11. 0 /  0.11. 0
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
  [x11grab @ 0x98e8420]device: :0.0+0,0 -> display: :0.0 x: 0 y: 0 width: 1680 height: 1050
  
  [x11grab @ 0x98e8420]shared memory extension  found
  
  X Error of failed request:  BadMatch (invalid parameter attributes)
  
    Major opcode of failed request:  140 (MIT-SHM)
  
    Minor opcode of failed request:  4 (X_ShmGetImage)
  
    Serial number of failed request:  11
  
    Current serial number in output stream:  11
  
  Warning: call to srand(1352225865)
  
  Warning: call to rand()
  
  Blocked: call to unsetenv("DBUS_ACTIVATION_ADDRESS")
  
  Blocked: call to unsetenv("DBUS_ACTIVATION_BUS_TYPE")
  
  [0x9782aec] dummy interface: using the dummy interface module...
  
  [0x987258c] main access out: creating httpd
  
  [0x98d0764] main stream error: cannot pre fill buffer

  Please help me to achieve this. Thanks in advance.

• convert WAV to TETRA format

  14 juin 2020, par Ashish Arora

  I am trying to convert a wav file into TETRA encoded file (https://en.wikipedia.org/wiki/Terrestrial_Trunked_Radio). Tetra is used by fire-fighters, it provides a radio-like voice.

  



  I am trying to use the official tetra codec codes available at (https://www.etsi.org/deliver/etsi_en/300300_300399/30039502/01.03.01_60/) and we can easily compile it using the scripts available at https://github.com/sq5bpf/install-tetra-codec.

  



  However, I am not able to figure out how to convert a wav file into tetra codec files using these files. I tried going through the documentation of the compiled files (ccoder, cdecoder, scoder, sdecoder).

  



  I tried the following command -

  



  


  tetra/bin/scoder input.wav serial_file synth_file

  


  



  here serial_file and synth_file are the output files and have following documentation in the scoder.c file :

  



      INPUT   :   - Description : speech file to be analyzed
                - Format : binary file 16 bit-samples
                  240 samples per frame

serial_file :   - Description : serial stream output file 
            - Format : binary file 16 bit-samples
              each 16 bit-sample represents one encoded bit
              138 (= 1 + 137) bits per frame

synth_file  :   - Description : local synthesis output file 
            - Format : binary file 16 bit-samples


  



  For an input file of size 13M, I obtained serial_file and synth_file of size 8.0M and 16M. However, I thought since the wav file is getting converted into a walkie-talkie type signal the output file size will be alot smaller.

  



  I want to clarify if :

  



  

  • I used the correct code to convert an input wav file into a tetra format output file.

  


  • can you please help me understand, what is serial_file and synth_file.

  


  



  Thanks,
Ashish

  


• How to decode and display real-time H264 stream using ffmpeg in Python ?

  25 mars 2022, par yiiiiiiiran

  I would like to port the live stream to ffmpeg and display it in real time using Python.

  


  Anyone knows how to port the stream to PIPE ? And in the mean time to display it after decoding ?

  


  I managed to get real-time stream from my Raspberry Pi3 to Windows PC, using RS232 connection with Baud Rate 2M.

  


  The format of the stream is in H264. The data package I get for each frame is in .
In order for the program to know when does each package ends, I've add

  


  bytes([0xcc,0xdd,0xee,0xff])


  


  to the end of package. So that my serial port will read for a package until it sees those bytes.

  


  Lets assume the stream WIDTH, HEIGHT, NUM_FRAMES, FPS = 320, 240, 90, 30

  


  I have the command for decode the h264 stream :

  


  cmd = ["C:/XXXXXX/ffmpeg.exe",
    "-probesize", "32",
    "-flags", "low_delay",
    "-f", "h264",
    "-i", "pipe:",
    "-f", "rawvideo", "-pix_fmt", "rgb24", "-s", "384x216",
    "pipe:"]

decode_process = sp.Popen(cmd, stdin=sp.PIPE, stdout=sp.PIPE)


  


  The stream package I got is

  


  while datetime.now() &lt; end_time:&#xA;    pkg = ser.read_until(expected=bytes([0xcc,0xdd,0xee,0xff])) #output <class>&#xA;    frame_len = len(pkg)-4&#xA;    frame_inBytes = pkg[0:frame_len]&#xA;    decode_process.stdin.write(frame_inBytes)&#xA;</class>

  


  I want to write the real time stream to PIPE however it shows error :

  


  [h264 @ 0000017322a3e980] missing picture in access unit with size 48
[h264 @ 0000017322a3e980] no frame!
[h264 @ 0000017322a2d240] Stream #0: not enough frames to estimate rate; consider increasing probesize
[h264 @ 0000017322a2d240] Could not find codec parameters for stream 0 (Video: h264, none): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (32) options        
Input #0, h264, from 'pipe:':
  Duration: N/A, bitrate: N/A
  Stream #0:0: Video: h264, none, 25 tbr, 1200k tbn
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
[h264 @ 0000017322a3f180] no frame!
Error while decoding stream #0:0: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF
Error marking filters as finished
Conversion failed!