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• Extracting Thumbnail URL from Video URL

  29 août 2023, par Deepak Sangle

  So, I have a video URL in an Amazon S3 bucket. I must extract the thumbnail image (preview image) from the video URL. The catch is that I do not have the luxury to download or upload the complete video since it takes time. My approach is something like this.
I first created a blob object containing the first few seconds of that video using something like this.

  


    const chunkSize = 1024*1024; // 1MB
  const start = 0;
  const end = chunkSize - 1;
  const rangeHeader = `bytes=${start}-${end}`;
  
  const VideoResponse = await axios.get(url, { 
    responseType: 'arraybuffer',
    headers: { Range: rangeHeader }
  });

  const chunkData = VideoResponse.data; 
  
  const videoBlob = new Blob([chunkData], { type: 'video/mp4' });
  const videoUrl = URL.createObjectURL(videoBlob);
  console.log({chunkData, videoBlob, videoUrl});


  


  Console gives me something like this

  


  {&#xA;  chunkData: <buffer 00="00" 1c="1c" 66="66" 74="74" 79="79" 70="70" 6d="6d" 34="34" 32="32" 69="69" 73="73" 6f="6f" 61="61" 76="76" 63="63" 31="31" 02="02" bd="bd" ab="ab" 6c="6c" 68="68" 64="64" c7="c7" 1048526="1048526" more="more" bytes="bytes">,&#xA;  videoBlob: Blob { size: 1048576, type: &#x27;video/mp4&#x27; },&#xA;  videoUrl: &#x27;blob:nodedata:764fce87-792f-47e8-bc3e-15921ee5787f&#x27;&#xA;}&#xA;</buffer>

  


  Now, there are many options after this. I am trying to download this blob object by converting it into a file. After I successfully convert it into an mp4 file, I can easily take a screenshot of it using fluent-ffmpeg package. However, I couldn't convert it into a file. If I try to do something like this

  


    const BlobResponse = await axios({
    method: 'GET',
    url: videoUrl,
    responseType: 'stream'
  });

  const file = fs.createWriteStream(`video.mp4`);
  BlobResponse.data.pipe(file);
  
  file.on("error", (error) => {
    console.log(`There was an error writing the file. Details: $ {error}`);
  });

  file.on('finish', () => {
    file.close();
    console.log("File downloaded successfully");
  });


  


  But it throws me the error AxiosError: Unsupported protocol blob:

  


  I also tried to directly convert the blob object to a jpeg object but to no avail.

  


  I have searched complete StackOverflow, and I have not found a single solution working so please let me know why those are not working or if there is any new solution to do this.

  


• Trying to grab video stream from a 802W device

  1er juin 2015, par brentil

  A group of us in the RC hobby forums had started trying to use a device called the 802W, it takes RCA in and then broadcasts it back out over a WiFi you connect to via an Android or iOS device. They’re typically used for backup camera addon systems for vehicles. We want to use it to do FPV (First Person Video/View) with using smartphones instead of buying more expensive FPV goggles.

  802W device example (plenty of clones online)

  http://www.amazon.com/Wireless-Backup-Camera-Transmitter-Android/dp/B00LJPTJSY

  The problem is you can only use their application WIFI_AVIN or WIFI_AVIN2 from the app stores to connect to it because they don’t publish the information about how to grab the stream data. We want to write our own apps that can use the stream to better show the information. We’ve tried using VLC to grab the stream from an Android phone or a Windows PC but we’ve had no success so far. I was hoping someone could look at the Wireshark outputs and might understand what they’re looking at better than I am. I "think" it’s a UDP multicast being broadcasted but I just don’t know enough to be sure. We’ve tried using VLC to connect to network streams directly on the device or from udp ://@ type addresses but I think part of the issue too might be we’re missing the file path of the stream file.

  Attempting to reverse engineer their code for learning purposes showed that ffmpeg is inside a compiled .so library which also seems to be where the actual connection code happens which we were unable to dig into.

  In the images 192.168.72.33 is my phone and 192.168.72.173 is the 802W device.

  Image of what I believe is a UDP broadcast of the video information.
  

  This is what the stream turns into when the device connects using the WIFI_AVIN application.
  

• Revision 30857 : On a rendu le plugin saisies nécessaire donc autant l’utiliser On ...

  12 août 2009, par kent1@… — Log

  On a rendu le plugin saisies nécessaire donc autant l’utiliser
  On améliore l’include inc-tags aussi ... s’il est correctement placé dans la page, il se recharge à chaque tag ajouté / supprimé