main.c

the mpeg2/4 aac decoder

            fprintf(stderr, "Error opening file: %s\n", adts_fn);
            return 1;
        }
    }

    b.infile = fopen(aacfile, "rb");
    if (b.infile == NULL)
    {
        /* unable to open file */
        fprintf(stderr, "Error opening file: %s\n", aacfile);
        return 1;
    }

    fseek(b.infile, 0, SEEK_END);
    fileread = ftell(b.infile);
    fseek(b.infile, 0, SEEK_SET);

    if (!(b.buffer = (unsigned char*)malloc(FAAD_MIN_STREAMSIZE*MAX_CHANNELS)))
    {
        fprintf(stderr, "Memory allocation error\n");
        return 0;
    }
    memset(b.buffer, 0, FAAD_MIN_STREAMSIZE*MAX_CHANNELS);

    bread = fread(b.buffer, 1, FAAD_MIN_STREAMSIZE*MAX_CHANNELS, b.infile);
    b.bytes_into_buffer = bread;
    b.bytes_consumed = 0;
    b.file_offset = 0;

    if (bread != FAAD_MIN_STREAMSIZE*MAX_CHANNELS)
        b.at_eof = 1;

    tagsize = 0;
    if (!memcmp(b.buffer, "ID3", 3))
    {
        /* high bit is not used */
        tagsize = (b.buffer[6] << 21) | (b.buffer[7] << 14) |
            (b.buffer[8] <<  7) | (b.buffer[9] <<  0);

        tagsize += 10;
        advance_buffer(&b, tagsize);
        fill_buffer(&b);
    }

    hDecoder = NeAACDecOpen();

    /* Set the default object type and samplerate */
    /* This is useful for RAW AAC files */
    config = NeAACDecGetCurrentConfiguration(hDecoder);
    if (def_srate)
        config->defSampleRate = def_srate;
    config->defObjectType = object_type;
    config->outputFormat = outputFormat;
    config->downMatrix = downMatrix;
    config->useOldADTSFormat = old_format;
    //config->dontUpSampleImplicitSBR = 1;
    NeAACDecSetConfiguration(hDecoder, config);

    /* get AAC infos for printing */
    header_type = 0;
    if ((b.buffer[0] == 0xFF) && ((b.buffer[1] & 0xF6) == 0xF0))
    {
        adts_parse(&b, &bitrate, &length);
        fseek(b.infile, tagsize, SEEK_SET);

        bread = fread(b.buffer, 1, FAAD_MIN_STREAMSIZE*MAX_CHANNELS, b.infile);
        if (bread != FAAD_MIN_STREAMSIZE*MAX_CHANNELS)
            b.at_eof = 1;
        else
            b.at_eof = 0;
        b.bytes_into_buffer = bread;
        b.bytes_consumed = 0;
        b.file_offset = tagsize;

        header_type = 1;
    } else if (memcmp(b.buffer, "ADIF", 4) == 0) {
        int skip_size = (b.buffer[4] & 0x80) ? 9 : 0;
        bitrate = ((unsigned int)(b.buffer[4 + skip_size] & 0x0F)<<19) |
            ((unsigned int)b.buffer[5 + skip_size]<<11) |
            ((unsigned int)b.buffer[6 + skip_size]<<3) |
            ((unsigned int)b.buffer[7 + skip_size] & 0xE0);

        length = (float)fileread;
        if (length != 0)
        {
            length = ((float)length*8.f)/((float)bitrate) + 0.5f;
        }

        bitrate = (int)((float)bitrate/1000.0f + 0.5f);

        header_type = 2;
    }

    *song_length = length;

    fill_buffer(&b);
    if ((bread = NeAACDecInit(hDecoder, b.buffer,
        b.bytes_into_buffer, &samplerate, &channels)) < 0)
    {
        /* If some error initializing occured, skip the file */
        fprintf(stderr, "Error initializing decoder library.\n");
        if (b.buffer)
            free(b.buffer);
        NeAACDecClose(hDecoder);
        fclose(b.infile);
        return 1;
    }
    advance_buffer(&b, bread);
    fill_buffer(&b);

    /* print AAC file info */
    fprintf(stderr, "%s file info:\n", aacfile);
    switch (header_type)
    {
    case 0:
        fprintf(stderr, "RAW\n\n");
        break;
    case 1:
        fprintf(stderr, "ADTS, %.3f sec, %d kbps, %d Hz\n\n",
            length, bitrate, samplerate);
        break;
    case 2:
        fprintf(stderr, "ADIF, %.3f sec, %d kbps, %d Hz\n\n",
            length, bitrate, samplerate);
        break;
    }

    if (infoOnly)
    {
        NeAACDecClose(hDecoder);
        fclose(b.infile);
        if (b.buffer)
            free(b.buffer);
        return 0;
    }

    do
    {
        sample_buffer = NeAACDecDecode(hDecoder, &frameInfo,
            b.buffer, b.bytes_into_buffer);

        if (adts_out == 1)
        {
            int skip = (old_format) ? 8 : 7;
            adtsData = MakeAdtsHeader(&adtsDataSize, &frameInfo, old_format);

            /* write the adts header */
            fwrite(adtsData, 1, adtsDataSize, adtsFile);

            /* write the frame data */
            if (frameInfo.header_type == ADTS)
                fwrite(b.buffer + skip, 1, frameInfo.bytesconsumed - skip, adtsFile);
            else
                fwrite(b.buffer, 1, frameInfo.bytesconsumed, adtsFile);
        }

        /* update buffer indices */
        advance_buffer(&b, frameInfo.bytesconsumed);

        if (frameInfo.error > 0)
        {
            fprintf(stderr, "Error: %s\n",
                NeAACDecGetErrorMessage(frameInfo.error));
        }

        /* open the sound file now that the number of channels are known */
        if (first_time && !frameInfo.error)
        {
            /* print some channel info */
            print_channel_info(&frameInfo);

            if (!adts_out)
            {
                /* open output file */
                if (!to_stdout)
                {
                    aufile = open_audio_file(sndfile, frameInfo.samplerate, frameInfo.channels,
                        outputFormat, fileType, aacChannelConfig2wavexChannelMask(&frameInfo));
                } else {
                    aufile = open_audio_file("-", frameInfo.samplerate, frameInfo.channels,
                        outputFormat, fileType, aacChannelConfig2wavexChannelMask(&frameInfo));
                }
                if (aufile == NULL)
                {
                    if (b.buffer)
                        free(b.buffer);
                    NeAACDecClose(hDecoder);
                    fclose(b.infile);
                    return 0;
                }
            } else {
                fprintf(stderr, "Writing output MPEG-4 AAC ADTS file.\n\n");
            }
            first_time = 0;
        }

        percent = min((int)(b.file_offset*100)/fileread, 100);
        if (percent > old_percent)
        {
            old_percent = percent;
            sprintf(percents, "%d%% decoding %s.", percent, aacfile);
            fprintf(stderr, "%s\r", percents);
#ifdef _WIN32
            SetConsoleTitle(percents);
#endif
        }

        if ((frameInfo.error == 0) && (frameInfo.samples > 0) && (!adts_out))
        {
            write_audio_file(aufile, sample_buffer, frameInfo.samples, 0);
        }

        /* fill buffer */
        fill_buffer(&b);

        if (b.bytes_into_buffer == 0)
            sample_buffer = NULL; /* to make sure it stops now */

    } while (sample_buffer != NULL);

    NeAACDecClose(hDecoder);

    if (adts_out == 1)
    {
        fclose(adtsFile);
    }

    fclose(b.infile);

    if (!first_time && !adts_out)
        close_audio_file(aufile);

    if (b.buffer)
        free(b.buffer);

    return frameInfo.error;
}

int GetAACTrack(mp4ff_t *infile)
{
    /* find AAC track */
    int i, rc;
    int numTracks = mp4ff_total_tracks(infile);

    for (i = 0; i < numTracks; i++)
    {
        unsigned char *buff = NULL;
        int buff_size = 0;
        mp4AudioSpecificConfig mp4ASC;

        mp4ff_get_decoder_config(infile, i, &buff, &buff_size);

        if (buff)
        {
            rc = NeAACDecAudioSpecificConfig(buff, buff_size, &mp4ASC);
            free(buff);

            if (rc < 0)
                continue;
            return i;
        }
    }

    /* can't decode this */
    return -1;
}

unsigned long srates[] =
{
    96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 16000,
    12000, 11025, 8000
};

int decodeMP4file(char *mp4file, char *sndfile, char *adts_fn, int to_stdout,
                  int outputFormat, int fileType, int downMatrix, int noGapless,
                  int infoOnly, int adts_out, float *song_length)
{
    int track;
    unsigned long samplerate;
    unsigned char channels;
    void *sample_buffer;

    mp4ff_t *infile;
    long sampleId, numSamples;

    audio_file *aufile;

    FILE *mp4File;
    FILE *adtsFile;
    unsigned char *adtsData;
    int adtsDataSize;

    NeAACDecHandle hDecoder;
    NeAACDecConfigurationPtr config;
    NeAACDecFrameInfo frameInfo;
    mp4AudioSpecificConfig mp4ASC;

    unsigned char *buffer;
    int buffer_size;

    char percents[200];
    int percent, old_percent = -1;

    int first_time = 1;

    /* for gapless decoding */
    unsigned int useAacLength = 1;
    unsigned int initial = 1;
    unsigned int framesize;
    unsigned long timescale;


    /* initialise the callback structure */
    mp4ff_callback_t *mp4cb = malloc(sizeof(mp4ff_callback_t));

    mp4File = fopen(mp4file, "rb");
    mp4cb->read = read_callback;
    mp4cb->seek = seek_callback;
    mp4cb->user_data = mp4File;


    hDecoder = NeAACDecOpen();

    /* Set configuration */
    config = NeAACDecGetCurrentConfiguration(hDecoder);
    config->outputFormat = outputFormat;
    config->downMatrix = downMatrix;
    //config->dontUpSampleImplicitSBR = 1;
    NeAACDecSetConfiguration(hDecoder, config);

    if (adts_out)
    {
        adtsFile = fopen(adts_fn, "wb");
        if (adtsFile == NULL)
        {
            fprintf(stderr, "Error opening file: %s\n", adts_fn);
            return 1;
        }
    }

    infile = mp4ff_open_read(mp4cb);
    if (!infile)
    {
        /* unable to open file */
        fprintf(stderr, "Error opening file: %s\n", mp4file);
        return 1;
    }

    if ((track = GetAACTrack(infile)) < 0)
    {
        fprintf(stderr, "Unable to find correct AAC sound track in the MP4 file.\n");
        NeAACDecClose(hDecoder);
        mp4ff_close(infile);
        free(mp4cb);
        fclose(mp4File);
        return 1;
    }

    buffer = NULL;
    buffer_size = 0;
    mp4ff_get_decoder_config(infile, track, &buffer, &buffer_size);

    if(NeAACDecInit2(hDecoder, buffer, buffer_size,
                    &samplerate, &channels) < 0)
    {
        /* If some error initializing occured, skip the file */
        fprintf(stderr, "Error initializing decoder library.\n");
        NeAACDecClose(hDecoder);
        mp4ff_close(infile);
        free(mp4cb);
        fclose(mp4File);
        return 1;
    }

    timescale = mp4ff_time_scale(infile, track);
    framesize = 1024;
    useAacLength = 0;

    if (buffer)
    {
        if (NeAACDecAudioSpecificConfig(buffer, buffer_size, &mp4ASC) >= 0)
        {
            if (mp4ASC.frameLengthFlag == 1) framesize = 960;
            if (mp4ASC.sbr_present_flag == 1) framesize *= 2;
        }
        free(buffer);
    }

    /* print some mp4 file info */
    fprintf(stderr, "%s file info:\n\n", mp4file);
    {
        char *tag = NULL, *item = NULL;
        int k, j;
        char *ot[6] = { "NULL", "MAIN AAC", "LC AAC", "SSR AAC", "LTP AAC", "HE AAC" };
        long samples = mp4ff_num_samples(infile, track);
        float f = 1024.0;
        float seconds;
        if (mp4ASC.sbr_present_flag == 1)
        {
            f = f * 2.0;
        }
        seconds = (float)samples*(float)(f-1.0)/(float)mp4ASC.samplingFrequency;

        *song_length = seconds;

        fprintf(stderr, "%s\t%.3f secs, %d ch, %d Hz\n\n", ot[(mp4ASC.objectTypeIndex > 5)?0:mp4ASC.objectTypeIndex],
            seconds, mp4ASC.channelsConfiguration, mp4ASC.samplingFrequency);

#define PRINT_MP4_METADATA
#ifdef PRINT_MP4_METADATA
        j = mp4ff_meta_get_num_items(infile);