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• ffmpeg : remove frames when audio mute

  23 septembre 2022, par dvt

  I have a video record of a public academic conference. For some reason, the audio is complete but intermittent(spectrogram sample). For each 5 10 secs, short mute interrupts, make me hard to focus on the content.
Thinking most of the video is static image, removing mute portion of the audio and corresponding frames might be a way to fix this.

  


  For now I've partially done using silenceremove and rubberband, stripping mute interruptions and stretch the audio to the same duration of the video. Steps below :

  


  


  1. Get the video duration with ffprobe
ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 sample.mp4

     


  


  2. Try silenceremove the audio once and Get its duration.

     


     ffmpeg -i "sample.mp4" -filter_complex "[a]silenceremove=stop_periods=-1:start_threshold=-50dB:stop_threshold=-50dB:detection=rms:window=0.01[a1]" -vn sample.wav
ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 sample.mp4


     


  


  3. Calculate the tempo manually (duration-audio/duration-video), for example I got 0.948.

     


  


  4. AIO command, rubberband added. Generate a fixed version from the source.

     


     ffmpeg -i "sample.mp4" -filter_complex "[a]silenceremove=stop_periods=-1:start_threshold=-50dB:stop_threshold=-50dB:detection=rms:window=0.01[a1];[a1]rubberband=tempo=0.948" -c:v copy -cutoff 7500 sample.fix.mp4

     


  


  


  I still wonder if there is a better way. Thanks guys.

  


  Refer :

  


  

  1. How to stretch the WAV file to the same video length ?

  


  2. How to trim out black frames with ffmpeg on windows ?

  


  


• Ffmpeg gentle stop sending [closed]

  31 mars 2023, par Ли Шеньшунь

  Good day. I'm trying to do a simple video sending and receiving on two computers that are on the same network. Video simulates streaming (video conference for example). I want to use ffmpeg but have run into a number of difficulties.
I start with two simple scripts :
Sender machine

  


  ffmpeg -re -i input_file.mp4 -c copy -f mpegts udp://192.168.2.10:1234


  


  recipient machine :

  


  ffmpeg -i udp://192.168.2.10:1234 -c copy save_video.mp4


  


  I got 2 questions :

  


  

  1. Is there a way to correctly end video reception when the sender does not send anything else ?

  


  


  The receive command works by waiting indefinitely. If the sender is still sending video and at this moment interrupt the receiver with ctrl+c, then the video is saved correctly. If the sender is finished, then after that, to stop, you need to use ctrl + c twice and the video is "broken", because. does not open apparently due to damage to the meta-data or codecs.

  


  I'm aware of options like using timeout, or saving to mkv format, they really work. But setting a specific number of seconds is problematic, and simply killing a process does not look very nice.

  


  

  2. Is the -re switch enough to simulate a "webcam" from a video file ? I heard that ffmpeg buffers packets in case of loss and can send them later later. I need to send it as it is, if there are any problems, then we lose the package forever. The -flush_packets key, as I understand it, is for writing to a file, but not when sending over the network.

  


  


• Can I use the file buffer or stream as input for fluent-ffmpeg ? I am trying to avoid saving the video locally to get its path before removing

  22 avril 2023, par Moath Thawahreh

  I am receiving the file via an api, I was trying to process the file.buffer as input for FFmpeg but it did not work, I had to save the video locally first and then process the path and remove the saved video later on.
I don't want to believe that there is no other way to solve this and I have been looking for solutions and workarounds but it was all about ffmpeg input as a path.

  


  I would love to find a solution using fluent-ffmpeg because it has some other great features, but I won't mind any suggestions for compressing the video using any different approaches if it's more efficient

  


  Again my code below works fine but I have to save the video and then remove it I am hoping for a more efficient solution :

  


    fs.writeFileSync(&#x27;temp.mp4&#x27;, file.buffer);&#xA;&#xA;    // Resize the temporary file using ffmpeg&#xA;    ffmpeg(&#x27;temp.mp4&#x27;) // here I tried pass file.buffer as readable stream,it receives paths only &#xA;      .format(&#x27;mp4&#x27;)&#xA;      .size(&#x27;50%&#x27;)&#xA;      .save(&#x27;resized.mp4&#x27;)&#xA;      .on(&#x27;end&#x27;, async () => {&#xA;        // Upload the resized file to Firebase&#xA;        const resizedFileStream = bucket.file(`video/${uniqueId}`).createWriteStream();&#xA;        fs.createReadStream(&#x27;resized.mp4&#x27;).pipe(resizedFileStream);&#xA;&#xA;        await new Promise<void>((resolve, reject) => {&#xA;          resizedFileStream&#xA;            .on(&#x27;finish&#x27;, () => {&#xA;              // Remove the local files after they have been uploaded&#xA;              fs.unlinkSync(&#x27;temp.mp4&#x27;);&#xA;              fs.unlinkSync(&#x27;resized.mp4&#x27;);&#xA;              resolve();&#xA;            })&#xA;            .on(&#x27;error&#x27;, reject);&#xA;        });&#xA;&#xA;        // Get the URL of the uploaded resized version&#xA;        const resizedFile = bucket.file(`video/${uniqueId}`);&#xA;        const url = await resizedFile.getSignedUrl({&#xA;          action: &#x27;read&#x27;,&#xA;          expires: &#x27;03-17-2025&#x27;, // Change this to a reasonable expiration date&#xA;        });&#xA;&#xA;        console.log(&#x27;Resized file uploaded successfully.&#x27;);&#xA;      })&#xA;      .on(&#x27;error&#x27;, (err) => {&#xA;        console.log(&#x27;An error occurred: &#x27; &#x2B; err.message);&#xA;      });&#xA;</void>