Sur d’autres sites (8453)

• CCTV DVR recovery

  5 juin 2014, par bitmadmax

  I need to recover footage from one of these unbranded CCTV DVR units. I am unable to gain access to the unit via a password, factory reset or backdoor, which would otherwise have let me "export" the footage.

  So I have pulled the hard disk and made a copy of it. The original unit is Linux-based which ran off a chip, and an EXT filesystem laid down on the hard disk itself. There is one partition which appears to contain the "raw" CCTV footage.

  The hex structure appears as though each frame begins with 00dcH264, 01dcH264, 10dcH264 and so on... I think the 00, 01, 10 etc refers to the channel/camera input number. The hex contents after the H264 portion appears completely random, of variable length and has no signature, and is followed immediately with the next xxdcH264 header.

  When I use ffprobe across the entire raw footage partition, it is only detecting the 1 video stream. I can use ffmpeg to "force" it to read it in as H.264 and dump it out into an MP4 file that I can play. However, this gives me the problem that the footage as an individual file is quite "noisy" and has frames from each channel appearing randomly.

  Is there anyway I could maybe separate out the footage into say a file for each channel ? I am not a great programmer so something as simple as possible would be ideal. I did note that ffprobe determined that some of the frames were of different resolution - it is likely that the different channels recorded their image at different dimensions, I just wondered if another way might be to get ffprobe/ffmpeg to output frames based on their image dimensions perhaps ?

  EDIT : sample hex below :

  Offset      0  1  2  3  4  5  6  7   8  9 10 11 12 13 14 15
  
  00000000   32 31 64 63 48 32 36 34  76 08 00 00 00 00 00 00   21dcH264v       
  
  00000016   1E 8B 77 07 6A 00 00 00  00 00 00 01 61 FC 03 51    ‹w j       aü Q
  
  00000032   42 83 FC C5 C6 BD 50 63  5F 37 68 B6 B5 B8 4F E0   BƒüÅƽPc_7h¶µ¸Oà
  
  00000048   2E 74 B8 FF BB BD 70 1C  DE 1E 7A 8C 0F            .t¸ÿ»½p Þ zŒ 

  (variable length)....

  Offset      0  1  2  3  4  5  6  7   8  9 10 11 12 13 14 15
  
  00000000   D3 30 59 01 FA 98 08 A0  0A 27 01 49 19 C1 0C 89   Ó0Y ú˜   ' I Á ‰
  
  00000016   83 AC 6B 28 03 8D 92 29  38 18 BA 95 82 B3 BA C6   ƒ¬k(  ’)8 º•‚³ºÆ
  
  00000032   33 0A 74 10 1A D5 89 3B  90 A0 19 1F A9 93 00 10   3 t  Õ‰;    ©“  
  
  00000048   92 AA 70 32 31 64 63 48  32 36 34                  ’ªp21dcH264

• Why my ffmpeg video encode codes does not work on other computer ?

  10 avril 2022, par Object Unknown

  I'm writing code to encode some cv::Mat images to a MP4 video. The program can run successfully in my computer which I developed it, but when I copied it (and all dlls it needs) to an other computer, it stopped work.

  


  The function which reporting error : (I got it from StackOverflow, and added some changes)

  


  int uns::VideoWriter::Remux()
{
    AVFormatContext* ifmt_ctx = NULL, * ofmt_ctx = NULL;
    int err = 0, ret = 0;
    int64_t ts = 0;
    AVStream* inVideoStream = NULL;
    AVStream* outVideoStream = NULL;
    if ((err = avformat_open_input(&ifmt_ctx, VIDEO_TMP_FILE.c_str(), 0, 0)) < 0)
    {
        if(callback != nullptr) 
            callback("[uns::VideoWriter/Remux] Failed to open input file for remuxing", err);
        ret = -1;
        goto end;
    }
    if ((err = avformat_find_stream_info(ifmt_ctx, 0)) < 0) 
    {
        if(callback != nullptr) 
            callback("[uns::VideoWriter/Remux] Failed to retrieve input stream information", err);
        ret = -2;
        goto end;
    }
    if ((err = avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, FINAL_FILE_NAME.c_str())))
    {
        if(callback != nullptr) 
            callback("[uns::VideoWriter/Remux] Failed to allocate output context", err);
        ret = -3;
        goto end;
    }
    inVideoStream = ifmt_ctx->streams[0];
    outVideoStream = avformat_new_stream(ofmt_ctx, NULL);
    if (!outVideoStream) 
    {
        if(callback != nullptr) 
            callback("[uns::VideoWriter/Remux] Failed to allocate output video stream", 0);
        ret = -4;
        goto end;
    }
    outVideoStream->time_base = { 1, fps };
    if ((err = avcodec_parameters_copy(outVideoStream->codecpar, inVideoStream->codecpar)) < 0)
    {
        if (callback != nullptr)
            callback("[uns::VideoWriter/Remux] Failed to copy stream information", err);
        return -4;
        goto end;
    }
    outVideoStream->codecpar->codec_tag = 0;
    if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) 
    {
        if ((err = avio_open(&ofmt_ctx->pb, FINAL_FILE_NAME.c_str(), AVIO_FLAG_WRITE)) < 0)
        {
            if(callback != nullptr) 
                callback("[uns::VideoWriter/Remux] Failed to open output file", err);
            ret = -5;
            goto end;
        }
    }
    ofmt_ctx->streams[0]->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    ofmt_ctx->streams[0]->time_base.num = 1;
    ofmt_ctx->streams[0]->time_base.den = fps;
    if ((err = avformat_write_header(ofmt_ctx, 0)) < 0) 
    {
        if(callback != nullptr) 
            callback("[uns::VideoWriter/Remux] Failed to write header to output file", err);
        ret = -6;
        goto end;
    }
    AVPacket videoPkt;
    while (true) 
    {
        if ((err = av_read_frame(ifmt_ctx, &videoPkt)) < 0) 
        {
            break;
        }
        videoPkt.stream_index = outVideoStream->index;
        videoPkt.pts = ts;
        videoPkt.dts = ts;
        videoPkt.duration = av_rescale_q(videoPkt.duration, inVideoStream->time_base, outVideoStream->time_base);
        ts += videoPkt.duration;
        videoPkt.pos = -1;
        if ((err = av_interleaved_write_frame(ofmt_ctx, &videoPkt)) < 0) 
        {
            if(callback != nullptr) 
                callback("[uns::VideoWriter/Remux] Failed to mux packet", err);
            av_packet_unref(&videoPkt);
            break;
        }
        av_packet_unref(&videoPkt);
    }
    av_write_trailer(ofmt_ctx);
end:
    if (ifmt_ctx) 
    {
        avformat_close_input(&ifmt_ctx);
    }
    if (ofmt_ctx && !(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) 
    {
        avio_closep(&ofmt_ctx->pb);
    }
    if (ofmt_ctx) 
    {
        avformat_free_context(ofmt_ctx);
    }
    return ret;
}


  


  Notes :

  


  


  callback is a function which prints error messsage and error code.

  
The error I recived is [uns::VideoWriter/Remux] Failed to write header to output file, error code: -22

  


  


  I want to know what is causing this and how to resolve it please.

  


  Other Informations :

  


  


  Developing Env :

  


  


  OS : Windows 11 Professional Workstation build 22593.ni_release
  
IDE : Visual Studio 2022
  
ffmpeg : 4.4.1
  
Installed ffmpeg library :
ffmpeg[avcodec],ffmpeg[avdevice],ffmpeg[avfilter],ffmpeg[avfilter],ffmpeg[avformat],ffmpeg[openh264],ffmpeg[swresample],ffmpeg[swscale]
  
Compile Settings : x64 Release
  

  


  


  


  


  Running Env which causing error :

  


  


  OS : Windows Server 2019 DataCenter
  
With all dlls VS2022 copied to release folder

  


  


  


• PHP - Read and write the same file hangs

  2 février 2016, par Adracat

  I’m trying to use FFMPEG to make some works with video on the server, and something I need to do is to get the progress of the process.

  I searched a little and I found this solution which tells to write the log into a file and then reading and parsing it.

  The problem

  What is driving me crazy is that I tell FFMPEG - with exec - (process A) to write the log into a file, but when I try to read it - with file_get_contents() - (process B) it does not show the contents until process A is finished (or interrupted the PHP script).

  So, when process A finishes or it says "PHP script timeout", then I can read the file as times as I want, refreshing the page (process B) and showing the contents at the time.

  What I’ve tried

  I’ve tried to use fopen() to create the file with w, w+ and a parameters, using - and without using - fclose(). I’ve tried to use also flock() just in case it gets faster to read to process B if it knows it’s already locked and does not have to wait, but then FFMPEG is not able to write into the file.

  I’ve searched for multithreading too, but I think there must be an easier and simpler way.

  I’ve used also CURL and HTTP context, as this link suggests, but no luck.

  I’ve tried, too, to use PHP-FFMPEG but it’s not supporting the last FFMPEG version, so I cannot use it.

  When I said before "(or interrupted the PHP script)" is because I tried to wait and, when PHP got a timeout, process B worked alright and the file was still updating.

  The code

  Process A (fileA.php)

  exec('ffmpeg -y -i input_file.mp4 output_file.avi 2> C:\Full\Path\To\File\log.txt 1>&2');

  Process B (fileB.php)

  $content = file_get_contents($file);
  
  
  
  if($content){
  
      //get duration of source
  
      preg_match("/Duration: (.*?), start:/", $content, $matches);
  
  
  
      $rawDuration = $matches[1];
  
  
  
      //rawDuration is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawDuration));
  
      $duration = floatval($ar[0]);
  
      if (!empty($ar[1])) $duration += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $duration += intval($ar[2]) * 60 * 60;
  
  
  
      //get the time in the file that is already encoded
  
      preg_match_all("/time=(.*?) bitrate/", $content, $matches);
  
  
  
      $rawTime = array_pop($matches);
  
  
  
      //this is needed if there is more than one match
  
      if (is_array($rawTime)){$rawTime = array_pop($rawTime);}
  
  
  
      //rawTime is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawTime));
  
      $time = floatval($ar[0]);
  
      if (!empty($ar[1])) $time += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $time += intval($ar[2]) * 60 * 60;
  
  
  
      //calculate the progress
  
      $progress = round(($time/$duration) * 100);
  
  
  
      echo "Duration: " . $duration . "<br />";
  
      echo "Current Time: " . $time . "<br />";
  
      echo "Progress: " . $progress . "%";
  
  
  
  }

  The process

  I just open fileA.php on a Chrome tab and, after a few seconds, I open fileB.php on another Chrome tab (and it stays as loading).

  What I need

  I need to be able to load the file and show the information I want to show while the file is being written (by exec and FFMPEG or other PHP scripts), so I can update the progress percentage with some AJAX calls.

  Extra information

  At this point, I’m using PHP 5.4 on a IIS 7.5 with Windows 7 Professional.

  Thank you everyone for your time, help and patience !

  Best regards.