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Autres articles (41)

  • Encoding and processing into web-friendly formats

    13 avril 2011, par

    MediaSPIP automatically converts uploaded files to internet-compatible formats.
    Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
    Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
    Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
    All uploaded files are stored online in their original format, so you can (...)

  • Support audio et vidéo HTML5

    10 avril 2011

    MediaSPIP utilise les balises HTML5 video et audio pour la lecture de documents multimedia en profitant des dernières innovations du W3C supportées par les navigateurs modernes.
    Pour les navigateurs plus anciens, le lecteur flash Flowplayer est utilisé.
    Le lecteur HTML5 utilisé a été spécifiquement créé pour MediaSPIP : il est complètement modifiable graphiquement pour correspondre à un thème choisi.
    Ces technologies permettent de distribuer vidéo et son à la fois sur des ordinateurs conventionnels (...)

  • HTML5 audio and video support

    13 avril 2011, par

    MediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
    The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
    For older browsers the Flowplayer flash fallback is used.
    MediaSPIP allows for media playback on major mobile platforms with the above (...)

Sur d’autres sites (6561)

  • How to save/encode recorded raw PCM Data as AAC/MP4 format file in Android

    28 janvier 2015, par INVISIBLE

    i want to save recorder pcm data as aac/mp4 format file.
    i am using AudioRecord class for recording audio in android. i have success fully saved it as wave file by adding a wave header to raw data. but dont know how to save it as aac/mp4 file, because aac/mp4 format is compressed then wave.
    the methods i am using for saving pcm data as wave is pasted below.

    recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
               SavedSampleRate, RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING,
               bufferSize);
    recorder.startRecording();
    isRecording = true;

    isRecording = true;

    recordingThread = new Thread(new Runnable() {
       @Override
       public void run() {
           writeAudioDataToFile();
       }
    }, "AudioRecorder Thread");

    recordingThread.start();

    second

    private void writeAudioDataToFile() {

       byte data[] = new byte[bufferSize];
       // short sData[] = new short[bufferSize];
       String filename = getTempFilename();
       FileOutputStream os = null;

       try {
           os = new FileOutputStream(filename);
       } catch (Exception e) {
           e.printStackTrace();
       }

       int read = 0;

       if (null != os) {
           while (isRecording) {
               double sum = 0;
               read = recorder.read(data, 0, bufferSize);

               if (AudioRecord.ERROR_INVALID_OPERATION != read) {
                   try {

                       synchronized (this) {


                           // Necessary in order to convert negative shorts!
                           final int USHORT_MASK = (1 << 16) - 1;

                           final ByteBuffer buf = ByteBuffer.wrap(data).order(
                                   ByteOrder.LITTLE_ENDIAN);

                           final ByteBuffer newBuf = ByteBuffer.allocate(
                                   data.length).order(ByteOrder.LITTLE_ENDIAN);

                           int sample;

                           while (buf.hasRemaining()) {



                               short shortSample = buf.getShort();
                               sample = (int) shortSample & USHORT_MASK;



                               sample = sample * db_value_global;
                               sample = mRmsFilterSetting.filter
                                       .apply((((int) 0) | shortSample)
                                               * db_value_global);



                               newBuf.putShort((short) sample);
                           }

                           data = newBuf.array();

                           os.write(data);





                       }

                   } catch (Exception e) {
                       e.printStackTrace();
                   }
               }
           }

           try {
               os.close();
           } catch (Exception e) {
               e.printStackTrace();
           }
       }
    }

    and finally saving it as

    private void copyWaveFile(ArrayList<string> inFilename, String outFilename) {
       FileInputStream[] in = null;
       FileOutputStream out = null;
       long totalAudioLen = 0;
       long totalDataLen = totalAudioLen + 36;
       long longSampleRate = SavedSampleRate;
       int channels = 2;
       long byteRate = RECORDER_BPP * SavedSampleRate * channels / 8;

       byte[] data = new byte[bufferSize];

       try {
           out = new FileOutputStream(outFilename);

           in = new FileInputStream[inFilename.size()];

           for (int i = 0; i &lt; in.length; i++) {
               in[i] = new FileInputStream(inFilename.get(i));
               totalAudioLen += in[i].getChannel().size();
           }

           totalDataLen = totalAudioLen + 36;

           WriteWaveFileHeader(out, totalAudioLen, totalDataLen,
                   longSampleRate, channels, byteRate);

           for (int i = 0; i &lt; in.length; i++) {
               while (in[i].read(data) != -1) {
                   out.write(data);
               }

               in[i].close();
           }

           out.close();
       } catch (Exception e) {
           e.printStackTrace();
       }
    }



    private void WriteWaveFileHeader(FileOutputStream out, long totalAudioLen,
           long totalDataLen, long longSampleRate, int channels, long byteRate)
           throws IOException {

       byte[] header = new byte[44];

       header[0] = 'R'; // RIFF/WAVE header
       header[1] = 'I';
       header[2] = 'F';
       header[3] = 'F';
       header[4] = (byte) (totalDataLen &amp; 0xff);
       header[5] = (byte) ((totalDataLen >> 8) &amp; 0xff);
       header[6] = (byte) ((totalDataLen >> 16) &amp; 0xff);
       header[7] = (byte) ((totalDataLen >> 24) &amp; 0xff);
       header[8] = 'W';
       header[9] = 'A';
       header[10] = 'V';
       header[11] = 'E';
       header[12] = 'f'; // 'fmt ' chunk
       header[13] = 'm';
       header[14] = 't';
       header[15] = ' ';
       header[16] = 16; // 4 bytes: size of 'fmt ' chunk
       header[17] = 0;
       header[18] = 0;
       header[19] = 0;
       header[20] = 1; // format = 1
       header[21] = 0;
       header[22] = (byte) channels;
       header[23] = 0;
       header[24] = (byte) (longSampleRate &amp; 0xff);
       header[25] = (byte) ((longSampleRate >> 8) &amp; 0xff);
       header[26] = (byte) ((longSampleRate >> 16) &amp; 0xff);
       header[27] = (byte) ((longSampleRate >> 24) &amp; 0xff);
       header[28] = (byte) (byteRate &amp; 0xff);
       header[29] = (byte) ((byteRate >> 8) &amp; 0xff);
       header[30] = (byte) ((byteRate >> 16) &amp; 0xff);
       header[31] = (byte) ((byteRate >> 24) &amp; 0xff);
       header[32] = (byte) (2 * 16 / 8); // block align
       header[33] = 0;
       header[34] = RECORDER_BPP; // bits per sample
       header[35] = 0;
       header[36] = 'd';
       header[37] = 'a';
       header[38] = 't';
       header[39] = 'a';
       header[40] = (byte) (totalAudioLen &amp; 0xff);
       header[41] = (byte) ((totalAudioLen >> 8) &amp; 0xff);
       header[42] = (byte) ((totalAudioLen >> 16) &amp; 0xff);
       header[43] = (byte) ((totalAudioLen >> 24) &amp; 0xff);

       out.write(header, 0, 44);
    }
    </string>

    in this piece of code i am recording small PCM files with AudioRecord and saving them as wave file by adding wave header.

    is there any step by step tutorial for how to save pcm data as mp4/aac file.

    thanks in advance.

  • MAINTAINERS : add myself to the general developers list

    26 avril 2020, par Limin Wang
    MAINTAINERS : add myself to the general developers list
    

    Signed-off-by : Limin Wang <lance.lmwang@gmail.com>
    Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>

    • [DH] MAINTAINERS
  • Meaning of "ffprobe -v trace demo.mp4" output

    17 mai 2019, par bluesky

    The ’mdat box’ of Mp4 file may at the last of file. I want to know the position of ’mdat’ box using ’ffmpeg’ or ’ffprobe’.

    Mp4 consists of ’ftyp’, ’moov’ and ’mdat’ BOX. each BOX consists of "BoxHeader" and "BoxData". "BoxHeader" consists of "BoxSize(4Byte)", "BoxType(4Byte)", "BoxLargesize(8Byte, only have when box size exceeding the range of 4Byte expression, then the value of BoxSize is 1)".

    In program, you could first read 8 Byte and know the size of ’ftyp box’, then seek the size and read 8 Byte to know if the next box is ’moov box’. If not ’moov’, it shoud be ’mdat box’, then seek cross ’mdat box’ to find ’mdat box’...

    But I want to use ’ffprobe’ to find the position of ’moov’. I use ’ffprobe -v trace demo.mp4’, and output is like below

    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fc8fd000e00] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fc8fd000e00] type:'ftyp' parent:'root' sz: 28 8 41044500
    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fc8fd000e00] ISO: File Type Major Brand: mp42
    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fc8fd000e00] type:'moov' parent:'root' sz: 17943 36 41044500
    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fc8fd000e00] type:'mvhd' parent:'moov' sz: 108 8 17935

    I want to know the meaning of type:'ftyp' parent:'root' sz: 28 8 41044500 :
    type:'ftyp' parent:'root'is easy to know, sz: 28 8 41044500 is really make me confused, I guess 28 is size of ftyp box,but the meaning of 8 41044500 is what ?

    Could you explain the meaning of sz: 28 8 41044500, and where could find the doc ?