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• writing jpg images from ffmpeg pipe

  18 septembre 2024, par seandoucette

  Using php to read an rtsp stream from an ffmpeg command utilizing image2pipe, I'm finding the images are truncated in some manner and only display a partial image. My task is to write unique jpg filenames at 30fps. Below is the php code. I've simplified the filename structure in this example for clarity. The script performs as expected with no obvious errors writing out 30fps consistently. I can't figure out what extraneous or missing information in the content is causing the output images to appear corrupt.

  


  $cmd = "ffmpeg -rtsp_transport tcp -framerate 30 -i rtsp://".$camera_url." -f image2pipe pipe:1";

$fp = popen($cmd, 'r');

if (!$fp)
{
    die('Could not open ffmpeg process');
}

define('JPEG_START', "\xFF\xD8");
define('JPEG_END', "\xFF\xD9");

$buffer = '';
$jpeg = '';
$isReadingJpeg = false;

stream_set_blocking($fp, false); // Set non-blocking mode

while (!feof($fp))
{
    $chunk = fread($fp, 4096);

    if ($chunk === false)
    {
        usleep(100);
        continue;
    }

    $buffer .= $chunk;

    if (!$isReadingJpeg && ($startPos = strpos($buffer, JPEG_START)) !== false)
    {
        $isReadingJpeg = true;
        $jpeg = substr($buffer, $startPos);
        $buffer = substr($buffer, $startPos + 2);  // Move past the start marker
    }

    if ($isReadingJpeg && ($endPos = strpos($buffer, JPEG_END)) !== false)
    {
        $jpeg .= substr($buffer, 0, $endPos + 2);
        $buffer = substr($buffer, $endPos + 2);  // Move past the end marker

        file_put_contents(microtime(true),$jpeg);

        $isReadingJpeg = false;
        $jpeg = '';
    }

    if ($isReadingJpeg)
    {
        $jpeg .= $buffer;
        $buffer = '';
    }
}

pclose($fp);


  


• ffmpeg pipe output and script [duplicate]

  27 juillet 2018, par James Magnus

  This question already has an answer here :

  • Execute command in a variable don’t execute the latter part of a pipe
    
    1 answer
    

  I need to extract raw video and pipe it to another program. This runs perfectly in a terminal :

  ffmpeg -i SampleVideo_1280x720_5mb.mp4 -s 1920x1080 -c:v rawvideo -pix_fmt yuv420p -f rawvideo - | ffplay -f rawvideo -pix_fmt yuv420p -s 1920x1080 -

  But when I try to run this command from a script it fails. Here is a very simplified version of the script :

  #!/bin/bash
  
  
  
  c='ffmpeg -i SampleVideo_1280x720_5mb.mp4 -s 1920x1080 -c:v rawvideo -pix_fmt yuv420p -f rawvideo - | ffplay -f rawvideo -pix_fmt yuv420p -s 1920x1080 -'
  
  $c

  The output

  ~/ets/videos$ ./test.sh 
  
  ffmpeg version N-91403-gd24c9e5 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
  
    configuration: --extra-cflags='-fPIC -I/home/jlbeaussart/ffmpeg_build/include' --extra-ldflags=-L/home/jlbeaussart/ffmpeg_build/lib --extra-libs='-lpthread -lm' --enable-gpl --enable-libaom --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-shared --enable-libcaca --enable-libxvid --enable-libxml2 --enable-opencl --enable-opengl --enable-cuvid --enable-ffnvcodec --enable-libdrm --enable-nvenc --enable-nvdec --enable-vaapi --enable-vdpau --enable-nonfree
  
    libavutil      56. 18.102 / 56. 18.102
  
    libavcodec     58. 20.104 / 58. 20.104
  
    libavformat    58. 17.101 / 58. 17.101
  
    libavdevice    58.  4.101 / 58.  4.101
  
    libavfilter     7. 25.100 /  7. 25.100
  
    libswscale      5.  2.100 /  5.  2.100
  
    libswresample   3.  2.100 /  3.  2.100
  
    libpostproc    55.  2.100 / 55.  2.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'SampleVideo_1280x720_5mb.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 1970-01-01T00:00:00.000000Z
  
      encoder         : Lavf53.24.2
  
    Duration: 00:00:29.57, start: 0.000000, bitrate: 1421 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1032 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        creation_time   : 1970-01-01T00:00:00.000000Z
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 383 kb/s (default)
  
      Metadata:
  
        creation_time   : 1970-01-01T00:00:00.000000Z
  
        handler_name    : SoundHandler
  
  [NULL @ 0x18d5d40] Unable to find a suitable output format for '|'
  
  |: Invalid argument

• Problem using ffmpeg in python to decode video stream to yuv stream and send to a pipe

  30 août 2019, par 瓦达所多阿萨德阿萨德

  This command works nice and fast in shell :

  ffmpeg -c:v h264_cuvid -i ./myvideo.mp4 -f null -pix-fmt yuv420p -

  It was about 13x speed or 300 frames/sec.
  Then I tried to send the yuv stream to pipe and catch it the main process using the following code in python :

  cmd = ['ffmpeg', '-c:v', 'h264_cuvid', '-i', './myvideo.mp4', '-f', 'image2pipe', '-pix_fmt', 'yuv420p', '-']
  
  p = subprocess.Popen(cmd, stdout = subprocess.PIPE, stderr=subprocess.PIPE)
  
  size_Y = int(height * width)
  
  size_UV = int(size_Y / 4)
  
  s = time.time()
  
  Y = p.stdout.read(size_Y)
  
  U = p.stdout.read(size_UV)
  
  V = p.stdout.read(size_UV)
  
  print('read time: ', time.time() - s)

  However, this took seconds to read just one yuv frame. What wronged here ? Im not sure what ffmpeg was sending into the pipe, the yuv planar frames or just the pointers to data planes ?

  the console output :

  [('Number of Frames', 61137), ('FPS', 25.0), ('Frame Shape', (1920, 1080))]
  
  --Number of Frames: 61137
  
  --FPS: 25.0
  
  --Frame Shape: (1920, 1080)
  
  cmd:  ['ffmpeg', '-c:v', 'h264_cuvid', '-i', './myvideo.mp4', '-f', 'image2pipe', '-pix_fmt', 'yuv420p', '-']
  
  read time:  5.251002073287964
  
  1/61137 (0.00%)read time:  2.290238618850708
  
  2/61137 (0.00%)read time:  1.2984871864318848
  
  3/61137 (0.00%)read time:  2.2100613117218018
  
  4/61137 (0.01%)read time:  2.3444178104400635