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• Trying to decode and encode audio files with the FFMPEG C API

  1er février 2023, par Giulio Iacomino

  My ultimate goal will be to split multi channel WAV files into single mono ones, after few days of experiments my plan is the sequence :

  


  

  1. Decode audio file into a frame.

  


  2. Convert interleaved frame into a planar one. (in order to separate the data buffer into multiple ones)

  


  3. Grab the planar frame buffers and encode each of them into a new file.

  


  


  So far I'm stuck trying to convert a wav file from interleaved to a planar one, and reprint the wav file.

  


  edit :
I've turned on guard malloc and apparently the error is within the convert function

  


  Here's the code :

  


  AVCodecContext* initializeAndOpenCodecContext(AVFormatContext* formatContext, AVStream* stream){
     // grab our stream, most audio files only have one anyway
    const AVCodec* decoder = avcodec_find_decoder(stream->codecpar->codec_id);
    if (!decoder){
        std::cout << "no decoder, can't go ahead!\n";
        return nullptr;
    }
    AVCodecContext* codecContext = avcodec_alloc_context3(decoder);
    avcodec_parameters_to_context(codecContext, stream->codecpar);
    int err = avcodec_open2(codecContext, decoder, nullptr);
    if (err < 0){
        std::cout << "couldn't open codex!\n";
    }
    return codecContext;
}

void initialiseResampler(SwrContext* resampler, AVFrame* inputFrame, AVFrame* outputFrame){
    av_opt_set_chlayout(resampler, "in_channel_layout", &inputFrame->ch_layout, 0);
    av_opt_set_chlayout(resampler, "out_channel_layout", &outputFrame->ch_layout, 0);
    av_opt_set_int(resampler, "in_sample_fmt", inputFrame->format, 0);
    av_opt_set_int(resampler, "out_sample_fmt", AV_SAMPLE_FMT_FLTP, 0);
    av_opt_set_int(resampler, "in_sample_rate", inputFrame->sample_rate, 0);
    av_opt_set_int(resampler, "out_sample_rate", outputFrame->sample_rate, 0);
}

AVFrame* initialisePlanarFrame(AVFrame* frameToInit, AVFrame* inputFrame){
    //AVFrame *planar_frame = av_frame_alloc();
    frameToInit->nb_samples = inputFrame->nb_samples;
    frameToInit->ch_layout = inputFrame->ch_layout;
    frameToInit->format = AV_SAMPLE_FMT_FLTP;
    frameToInit->sample_rate = inputFrame->sample_rate;
    return nullptr;
}

int main() {
    AVCodecContext *codingContext= NULL;
    const AVCodec *codec;
    codec = avcodec_find_encoder(AV_CODEC_ID_PCM_F32LE);
    codingContext = avcodec_alloc_context3(codec);
    codingContext->bit_rate = 16000;
    codingContext->sample_fmt = AV_SAMPLE_FMT_FLT;
    codingContext->sample_rate = 48000;
    codingContext->ch_layout.nb_channels = 2;
    codingContext->ch_layout.order = (AVChannelOrder)0;
    uint8_t **buffer_ = NULL;
    AVFrame* planar_frame = NULL;
    
    // open input
    AVFormatContext* formatContext = nullptr;
    int err = avformat_open_input(&formatContext, "/Users/tonytorm/Desktop/drum kits/DECAP - Drums That Knock Vol. 9/Kicks/Brash Full Metal Kick.wav", nullptr, nullptr);
    if (err < 0){
        fprintf(stderr, "Unable to open file!\n");
        return;
    }

    // find audio stream
    err = avformat_find_stream_info(formatContext, nullptr);
    if (err > 0){
        fprintf(stderr, "Unable to retrieve stream info!\n");
        return;
    }
    
    int index = av_find_best_stream(formatContext, AVMEDIA_TYPE_AUDIO, -1, -1, nullptr, 0);
    if (index < 0){
        std::cout<<  "coudn't find audio stream in this file" << '\n';
    }
    AVStream* stream = formatContext->streams[index];
    
    auto fileName = "/Users/tonytorm/Desktop/newFile.wav";
    FILE* newFile = fopen(fileName, "w+");
    
    // find right codec and open it
    if (auto openCodecContext = initializeAndOpenCodecContext(formatContext, stream)){
        AVPacket* packet = av_packet_alloc();
        AVFrame* frame = av_frame_alloc();
        AVFrame* planar_frame = av_frame_alloc();
        SwrContext *avr = swr_alloc();  //audio resampling context
        AVChannelLayout monoChannelLayout{(AVChannelOrder)0};
        monoChannelLayout.nb_channels = 2;
        

        while (!av_read_frame(formatContext, packet)){
            if (packet->stream_index != stream->index) continue;  // we only care about audio
            int ret = avcodec_send_packet(openCodecContext, packet);
            if ( ret < 0) {
                if (ret != AVERROR(EAGAIN)){   // if error is actual error not EAGAIN
                    std::cout << "can't do shit\n";
                    return;
                }
            }
            while (int bret = avcodec_receive_frame(openCodecContext, frame) == 0){
                initialisePlanarFrame(planar_frame, frame);
                
   
                
                int buffer_size_in = av_samples_get_buffer_size(nullptr,
                                                                frame->ch_layout.nb_channels,
                                                                frame->nb_samples,
                                                                (AVSampleFormat)frame->format,
                                                                0);
                int buffer_size_out = buffer_size_in/frame->ch_layout.nb_channels;

                //planar_frame->linesize[0] = buffer_size_out;
                
                int ret = av_samples_alloc(planar_frame->data,
                                           NULL,
                                           planar_frame->ch_layout.nb_channels,
                                           planar_frame->nb_samples,
                                           AV_SAMPLE_FMT_FLTP,
                                           0);
                
                initialiseResampler(avr, frame, planar_frame);
                if (int errRet = swr_init(avr) < 0) {
                    fprintf(stderr, "Failed to initialize the resampling context\n");
                }

                if (ret < 0){
                    char error_message[AV_ERROR_MAX_STRING_SIZE];
                    av_strerror(ret, error_message, AV_ERROR_MAX_STRING_SIZE);
                    fprintf(stderr, "Error allocating sample buffer: %s\n", error_message);
                    return -1;
                }
                
                int samples_converted = swr_convert(avr,
                                                    planar_frame->data,
                                                    buffer_size_out,
                                                    (const uint8_t **)frame->data,
                                                    buffer_size_in);
                if (samples_converted < 0) {
                    // handle error
                    std::cout << "error in conversion\n";
                    return;
                }
                if (avcodec_open2(codingContext, codec, NULL) < 0) {
                    std::cout << "can't encode!\n";
                    return;
                }
                AVPacket* nu_packet = av_packet_alloc();
                while (int copy = avcodec_send_frame(codingContext, planar_frame) != 0){
                    if (copy == AVERROR(EAGAIN) || copy == AVERROR_EOF){
                        std::cout << "can't encode file\n";
                        return;
                    }
                    if (avcodec_receive_packet(codingContext, nu_packet) >=0){
                        fwrite(nu_packet->data, 4, nu_packet->size, newFile);
                        //av_write_frame(avc, nu_packet);
                    }
                }
                av_freep(planar_frame->data);
                av_frame_unref(frame);
                av_frame_unref(planar_frame);
            }
//            av_packet_free(&packet);
//            av_packet_free(&nu_packet);
        }
        swr_free(&avr);
        avcodec_free_context(&codingContext);
        
    }
    fclose(newFile);
}


  


  I know i should write a header to the new wave file but for now I'm just trying to write the raw audio data. I'm getting always the same error but in different parts of the code (randomly), sometimes the code even compiles (writing the raw audio data, but filling it with some rubbish as well, i end up with a data file that is thrice the original one, sometimes i end up with a slightly smaller file - i guess the raw audio without the headers), results are basically random.

  


  Here are some of the functions that trigger the error :

  


  int ret = av_samples_alloc(); //(this the most common one)
swr_convert()
av_freep();


  


  the error is :

  


  main(64155,0x101b5d5c0) malloc: Incorrect checksum for freed object 0x106802600: probably modified after being freed.
Corrupt value: 0x0
main(64155,0x101b5d5c0) malloc: *** set a breakpoint in malloc_error_break to debug */


  


• Error : Cannot find ffmpeg in firebase cloud function

  6 novembre 2024, par Ahmed Wagdi

  i'm trying to compress some uploaded files to firebase storage .. using firebase cloud functions but it give me the error Error: Cannot find ffmpeg

  


  here is my function :

  


  const functions = require("firebase-functions");
const admin = require("firebase-admin");
const ffmpeg = require("fluent-ffmpeg");
const ffmpegStatic = require("ffmpeg-static");
const axios = require("axios");

// const {onSchedule} = require("firebase-functions/v2/scheduler");

admin.initializeApp();

// Ensure fluent-ffmpeg uses the binary
ffmpeg.setFfmpegPath(ffmpegStatic.path);

const db = admin.firestore();
const bucket = admin.storage().bucket();
const fs = require("fs");
const downloadVideo = async (url, outputPath) => {
  const response = await axios.get(url, {responseType: "stream"});
  const writer = fs.createWriteStream(outputPath);
  response.data.pipe(writer);
  return new Promise((resolve, reject) => {
    writer.on("finish", () => resolve(outputPath));
    writer.on("error", reject);
  });
};

const compressVideo = (videoFullPath, outputFileName, targetSize) => {
  return new Promise((resolve, reject) => {
    ffmpeg.ffprobe(videoFullPath, (err, metadata) => {
      if (err) return reject(err);
      const duration = parseFloat(metadata.format.duration);
      const targetTotalBitrate =
      (targetSize * 1024 * 8) / (1.073741824 * duration);

      let audioBitrate =
      metadata.streams.find((s) => s.codec_type === "audio").bit_rate;
      if (10 * audioBitrate > targetTotalBitrate) {
        audioBitrate = targetTotalBitrate / 10;
      }

      const videoBitrate = targetTotalBitrate - audioBitrate;
      ffmpeg(videoFullPath)
          .output(outputFileName)
          .videoCodec("libx264")
          .audioCodec("aac")
          .videoBitrate(videoBitrate)
          .audioBitrate(audioBitrate)
          .on("end", resolve)
          .on("error", reject)
          .run();
    });
  });
};

const uploadVideoWithResumableUpload = (filePath, destinationBlobName) => {
  const blob = bucket.file(destinationBlobName);
  const options = {resumable: true, validation: "crc32c"};
  return blob.createWriteStream(options).end(fs.readFileSync(filePath));
};

exports.processLessonsOnDemand =
functions.https.onRequest({timeoutSeconds: 3600, memory: "2GB"}
    , async (context) => {
      console.log("Fetching lessons from Firestore...");
      const lessonsRef = db.collection("leassons");
      const lessonsSnapshot = await lessonsRef.get();

      if (lessonsSnapshot.empty) {
        console.log("No lessons found in Firestore.");
        return; // Exit if no lessons are available
      }

      const lessonDoc = lessonsSnapshot.docs[0]; // Get the first document
      const lessonData = lessonDoc.data();

      if (lessonData.shrinked) {
        console.log(
            `Skipping lesson ID ${lessonDoc.id} as it's already shrunk.`,
        );
        return; // Exit if the first lesson is already shrunk
      }

      const videoURL = lessonData.videoURL;
      if (!videoURL) {
        console.log(
            `No video URL for lesson ID: ${lessonDoc.id}. Skipping...`,
        );
        return; // Exit if no video URL is available
      }

      const tempVideoPath = "/tmp/temp_video.mp4";

      try {
        await downloadVideo(videoURL, tempVideoPath);

        const targetSize = (fs.statSync(tempVideoPath).size * 0.30) / 1024;
        const outputCompressedVideo = `/tmp/compressed_${lessonDoc.id}.mp4`;

        await compressVideo(tempVideoPath, outputCompressedVideo, targetSize);

        await uploadVideoWithResumableUpload(
            outputCompressedVideo,
            `compressed_videos/compressed_${lessonDoc.id}.mp4`,
        );

        const newVideoURL = `https://storage.googleapis.com/${bucket.name}/compressed_videos/compressed_${lessonDoc.id}.mp4`;

        const oldVideoPath = videoURL.replace(`https://storage.googleapis.com/${bucket.name}/`, "");
        const oldBlob = bucket.file(oldVideoPath);
        await oldBlob.delete();

        await lessonsRef.doc(lessonDoc.id).update({
          videoURL: newVideoURL,
          shrinked: true,
        });

        console.log(`Processed lesson ID: ${lessonDoc.id}`);
        fs.unlinkSync(tempVideoPath); // Clean up temporary files
        fs.unlinkSync(outputCompressedVideo); // Clean up compressed file
      } catch (error) {
        console.error(`Error processing lesson ID ${lessonDoc.id}:`, error);
      }
    });




  


• Help us Reset The Net today on June 5th

  5 juin 2014, par Piwik Core Team — Community, Meta

  This blog post explains why the Piwik project is joining ResetTheNet online protest and how you can help make a difference against mass surveillance. It also includes an infographic and links to useful resources which may be of interest to you.

  Snowden revelations, a year ago today

  On June 5, 2013 the Guardian newspaper published the first of Edward Snowden’s astounding revelations. It was the first of a continuous stream of stories that pointed out what we’ve suspected for a long time : that the world’s digital communications are being continuously spied upon by nation states with precious little oversight.

  Unfortunately, mass surveillance is affecting the internet heavily. The Internet is a powerful force that can promote democracy, innovation, and creativity, but it’s being subverted as a tool for government spying. That is why Piwik has decided to join Reset The Net.

  June 5, 2014 marks a new year : a year that will not just be about listening to the inside story of mass surveillance, but a new year of fighting back !

  How do I protect myself and others ?

  Reset the Net is asking everyone to help by installing free software tools that are designed to protect your privacy on a computer or a mobile device.

  Reset the Net is also calling on websites and developers to add surveillance resistant features such as HTTPS and forward secrecy.

  Participate in ResetTheNet online protest

  Have you got your own website, blog or tumblr ? Maybe you can show the Internet Defense League’s “Cat Signal !” on your website.Get the code now to run the Reset the Net splash screen or banner to help make privacy viral on June 5th.

  Message from Edward Snowden

  Evan from FFTF sent us this message from Edward Snowden and we thought we would share it with you :

  One year ago, we learned that the internet is under surveillance, and our activities are being monitored to create permanent records of our private lives — no matter how innocent or ordinary those lives might be.

  Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same. That’s why I’m asking you to join me on June 5th for Reset the Net, when people and companies all over the world will come together to implement the technological solutions that can put an end to the mass surveillance programs of any government. This is the beginning of a moment where we the people begin to protect our universal human rights with the laws of nature rather than the laws of nations.

  We have the technology, and adopting encryption is the first effective step that everyone can take to end mass surveillance. That’s why I am excited for Reset the Net — it will mark the moment when we turn political expression into practical action, and protect ourselves on a large scale.

  Join us on June 5th, and don’t ask for your privacy. Take it back.

  – Message by Edward Snowden

  ResetTheNet privacy pack infographic

  

  Additional Resources

  Configure Piwik for Security and Privacy

  • Turn on automatic SSL redirection in your Piwik.
  • Configure Piwik for advanced Privacy.
  • Best security practises for Piwik.

  More info

  • Learn why this matters (EFF)
  • Data Privacy Day – Why is privacy important ? (Piwik)
  • Web Analytics Privacy (Piwik)