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• Revision 88566 : Le fichier vides.txt peut etre tres gros et est un peu lourd a ...

  11 avril 2015, par cedric@… — Log

  Le fichier vides.txt peut etre tres gros et est un peu lourd a manipuler. On le remplace par un fichier unitaire .vide sur chaque gravatar concerne, ce qui permet un touch unitaire avant une recuperation pour eviter une double recuperation concurrente (idem sur le cache, on touch avant de recuperer pour eviter une double recuperation)

• ffmpeg alternative to -ss to something with % ? [duplicate]

  9 juin 2020, par Akhilleus Uggo

  Is there anyway to start cutting a video, or indicate the start point by a percent of the video ?

  



  Let's suppose a video has a duration of 40 minutes. Starting at 25% of the video would be -ss 600, but not all videos are 40 minutes.

  



  Any replacement for -ss to something working by % ?

  


• how to add effect to audio, sound like a phone call phone, inner monologue, or sounds like a man/woman ? [closed]

  7 mars, par Mathew

  I'm trying to apply different audio effects, such as making audio sound like a phone call. Below is my current approach. As you can see, I'm using multiple filters and simple algorithms to achieve this effect, but the output quality isn't ideal.

  


  I've looked into FFmpeg filters and noticed mentions of LADSPA/LV2 plugins. Are these viable solutions ? Any other suggestions would be greatly appreciated.

  


  public static void applySceneEffect(String inputPath, String outputPath, int sceneType) {
    LOGGER.info("apply scene effect {} to {}", sceneType, inputPath);

    try (FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(inputPath);
         FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputPath, grabber.getAudioChannels())) {

        grabber.setOption("vn", ""); 
        grabber.start();

       
        recorder.setAudioCodec(avcodec.AV_CODEC_ID_PCM_S16LE); 
        recorder.setSampleRate(grabber.getSampleRate());
        recorder.setAudioChannels(grabber.getAudioChannels());
        recorder.setAudioBitrate(grabber.getAudioBitrate());
        recorder.setFormat("wav"); 


        String audioFilter = String.join(",",
                "aresample=8000",      
                "highpass=f=300, lowpass=f=3400",       
                "acompressor=threshold=-15dB:ratio=4:attack=10:release=100", 
                "volume=1.5",          
                "aecho=0.9:0.4:10:0.6"
        );

        FFmpegFrameFilter f1 = new FFmpegFrameFilter(audioFilter, grabber.getAudioChannels());
        f1.setSampleRate(grabber.getSampleRate());
        f1.start();

        recorder.start();

        Random random = new Random();
        double noiseLevel = 0.02; 

   
        while (true) {
            var frame = grabber.grabFrame(true, false, true, true);
            if (frame == null) {
                break;
            }

            ShortBuffer audioBuffer = (ShortBuffer) frame.samples[0];
            short[] audioData = new short[audioBuffer.remaining()];
            audioBuffer.get(audioData);

            applyElectricNoise(audioData, grabber.getSampleRate());

            audioData = applyDistortion(audioData, 1.5, 30000);

            audioBuffer.rewind();
            audioBuffer.put(audioData);
            audioBuffer.flip();


            f1.push(frame); 
            Frame filteredFrame;
            while ((filteredFrame = f1.pull()) != null) {
                recorder.record(filteredFrame); 
            }
        }

        recorder.stop();
        recorder.release();
        grabber.stop();
        grabber.release();
    } catch (FrameGrabber.Exception | FrameRecorder.Exception | FFmpegFrameFilter.Exception e) {
        throw new RuntimeException(e);
    }
}


private static final double NOISE_LEVEL = 0.005; 
private static final int NOISE_FREQUENCY = 60;  

public static void applyElectricNoise(short[] audioData, int sampleRate) {
    Random random = new Random();

    
    for (int i = 0; i < audioData.length; i++) {
        double noise = Math.sin(2 * Math.PI * NOISE_FREQUENCY * i / sampleRate);

        double electricNoise = random.nextGaussian() * NOISE_LEVEL * Short.MAX_VALUE + noise;

        audioData[i] = (short) Math.max(Math.min(audioData[i] + electricNoise, Short.MAX_VALUE), Short.MIN_VALUE); 
    }
}

public static short[] applyTremolo(short[] audioData, int sampleRate, double frequency, double depth) {
    double phase = 0.0;
    double phaseIncrement = 2 * Math.PI * frequency / sampleRate;

    for (int i = 0; i < audioData.length; i++) {
        double modulator = 1.0 - depth + depth * Math.sin(phase); 
        audioData[i] = (short) (audioData[i] * modulator);

        phase += phaseIncrement;
        if (phase > 2 * Math.PI) {
            phase -= 2 * Math.PI;
        }
    }
    return audioData;
}

public static short[] applyDistortion(short[] audioData, double gain, double threshold) {
    for (int i = 0; i < audioData.length; i++) {
        double sample = audioData[i] * gain;

        if (sample > threshold) {
            sample = threshold;
        } else if (sample < -threshold) {
            sample = -threshold;
        }

        audioData[i] = (short) sample;
    }
    return audioData;
}