flac.c

video linux conference

            i_channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
            break;
        case 1:
            i_channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
            break;
        case 2:
            i_channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
            break;
        default:
            return 0;
            break;
        }
#endif

        *pi_channels = 2;
    }
    else
    {
        *pi_channels = i_temp + 1;
        *pi_channels_conf = pi_channels_maps[ *pi_channels ];
    }

    /* Find bits per sample */
    switch( i_temp = (unsigned)(p_buf[3] & 0x0e) >> 1 )
    {
    case 0:
        if( p_sys->b_stream_info )
            *pi_bits_per_sample = p_sys->stream_info.bits_per_sample;
        else
            return 0;
        break;

    case 1:
        *pi_bits_per_sample = 8;
        break;

    case 2:
        *pi_bits_per_sample = 12;
        break;

    case 4:
        *pi_bits_per_sample = 16;
        break;

    case 5:
        *pi_bits_per_sample = 20;
        break;

    case 6:
        *pi_bits_per_sample = 24;
        break;

    case 3:
    case 7:
        return 0;
        break;
    }

    /* Zero padding bit */
    if( p_buf[3] & 0x01 ) return 0;

    /* End of fixed size header */
    i_header = 4;

    /* Find Sample/Frame number */
    if( i_blocksize_hint && b_variable_blocksize )
    {
        i_sample_number = read_utf8( &p_buf[i_header++], &i_read );
        if( i_sample_number == I64C(0xffffffffffffffff) ) return 0;
    }
    else
    {
        i_sample_number = read_utf8( &p_buf[i_header++], &i_read );
        if( i_sample_number == I64C(0xffffffffffffffff) ) return 0;

        if( p_sys->b_stream_info )
            i_sample_number *= p_sys->stream_info.min_blocksize;
    }

    i_header += i_read;

    /* Read blocksize */
    if( i_blocksize_hint )
    {
        int i_val1 = p_buf[i_header++];
        if( i_blocksize_hint == 7 )
        {
            int i_val2 = p_buf[i_header++];
            i_val1 = (i_val1 << 8) | i_val2;
        }
        i_blocksize = i_val1 + 1;
    }

    /* Read sample rate */
    if( i_sample_rate_hint )
    {
        int i_val1 = p_buf[i_header++];
        if( i_sample_rate_hint != 12 )
        {
            int i_val2 = p_buf[i_header++];
            i_val1 = (i_val1 << 8) | i_val2;
        }
        if( i_sample_rate_hint == 12 ) *pi_sample_rate = i_val1 * 1000;
        else if( i_sample_rate_hint == 13 ) *pi_sample_rate = i_val1;
        else *pi_sample_rate = i_val1 * 10;
    }

    /* Check the CRC-8 byte */
    if( flac_crc8( p_buf, i_header ) != p_buf[i_header] )
    {
        return 0;
    }

    return i_blocksize;
}

/* Will return 0xffffffffffffffff for an invalid utf-8 sequence */
static uint64_t read_utf8( const uint8_t *p_buf, int *pi_read )
{
    uint64_t i_result = 0;
    unsigned i, j;

    if( !(p_buf[0] & 0x80) ) /* 0xxxxxxx */
    {
        i_result = p_buf[0];
        i = 0;
    }
    else if( p_buf[0] & 0xC0 && !(p_buf[0] & 0x20) ) /* 110xxxxx */
    {
        i_result = p_buf[0] & 0x1F;
        i = 1;
    }
    else if( p_buf[0] & 0xE0 && !(p_buf[0] & 0x10) ) /* 1110xxxx */
    {
        i_result = p_buf[0] & 0x0F;
        i = 2;
    }
    else if( p_buf[0] & 0xF0 && !(p_buf[0] & 0x08) ) /* 11110xxx */
    {
        i_result = p_buf[0] & 0x07;
        i = 3;
    }
    else if( p_buf[0] & 0xF8 && !(p_buf[0] & 0x04) ) /* 111110xx */
    {
        i_result = p_buf[0] & 0x03;
        i = 4;
    }
    else if( p_buf[0] & 0xFC && !(p_buf[0] & 0x02) ) /* 1111110x */
    {
        i_result = p_buf[0] & 0x01;
        i = 5;
    }
    else if( p_buf[0] & 0xFE && !(p_buf[0] & 0x01) ) /* 11111110 */
    {
        i_result = 0;
        i = 6;
    }
    else {
        return I64C(0xffffffffffffffff);
    }

    for( j = 1; j <= i; j++ )
    {
        if( !(p_buf[j] & 0x80) || (p_buf[j] & 0x40) ) /* 10xxxxxx */
        {
            return I64C(0xffffffffffffffff);
        }
        i_result <<= 6;
        i_result |= (p_buf[j] & 0x3F);
    }

    *pi_read = i;
    return i_result;
}

/* CRC-8, poly = x^8 + x^2 + x^1 + x^0, init = 0 */
static uint8_t const flac_crc8_table[256] = {
        0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
        0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
        0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
        0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
        0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
        0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
        0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
        0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
        0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
        0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
        0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
        0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
        0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
        0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
        0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
        0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
        0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
        0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
        0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
        0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
        0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
        0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
        0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
        0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
        0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
        0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
        0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
        0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
        0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
        0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
        0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
        0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
};

static uint8_t flac_crc8( const uint8_t *data, unsigned len )
{
    uint8_t crc = 0;

    while(len--)
        crc = flac_crc8_table[crc ^ *data++];

    return crc;
}

#ifdef USE_LIBFLAC
/*****************************************************************************
 * encoder_sys_t : flac encoder descriptor
 *****************************************************************************/
struct encoder_sys_t
{
    /*
     * Input properties
     */
    int i_headers;

    int i_samples_delay;
    int i_channels;

    FLAC__int32 *p_buffer;
    int         i_buffer;

    block_t *p_chain;

    /*
     * FLAC properties
     */
    FLAC__StreamEncoder *p_flac;
    FLAC__StreamMetadata_StreamInfo stream_info;

    /*
     * Common properties
     */
    mtime_t i_pts;
};

#define STREAMINFO_SIZE 38

static block_t *Encode( encoder_t *, aout_buffer_t * );

static FLAC__StreamEncoderWriteStatus
EncoderWriteCallback( const FLAC__StreamEncoder *encoder,
                      const FLAC__byte buffer[],
                      unsigned bytes, unsigned samples,
                      unsigned current_frame, void *client_data );

static void EncoderMetadataCallback( const FLAC__StreamEncoder *encoder,
                                     const FLAC__StreamMetadata *metadata,
                                     void *client_data );

/*****************************************************************************
 * OpenEncoder: probe the encoder and return score
 *****************************************************************************/
static int OpenEncoder( vlc_object_t *p_this )
{
    encoder_t *p_enc = (encoder_t *)p_this;
    encoder_sys_t *p_sys;

    if( p_enc->fmt_out.i_codec != VLC_FOURCC('f','l','a','c') &&
        !p_enc->b_force )
    {
        return VLC_EGENERIC;
    }

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_sys = (encoder_sys_t *)malloc(sizeof(encoder_sys_t)) ) == NULL )
    {
        msg_Err( p_enc, "out of memory" );
        return VLC_EGENERIC;
    }
    p_enc->p_sys = p_sys;
    p_enc->pf_encode_audio = Encode;
    p_enc->fmt_out.i_codec = VLC_FOURCC('f','l','a','c');

    p_sys->i_headers = 0;
    p_sys->p_buffer = 0;
    p_sys->i_buffer = 0;
    p_sys->i_samples_delay = 0;

    /* Create flac encoder */
    p_sys->p_flac = FLAC__stream_encoder_new();

    FLAC__stream_encoder_set_streamable_subset( p_sys->p_flac, 1 );
    FLAC__stream_encoder_set_channels( p_sys->p_flac,
                                       p_enc->fmt_in.audio.i_channels );
    FLAC__stream_encoder_set_sample_rate( p_sys->p_flac,
                                          p_enc->fmt_in.audio.i_rate );
    FLAC__stream_encoder_set_bits_per_sample( p_sys->p_flac, 16 );
    p_enc->fmt_in.i_codec = AOUT_FMT_S16_NE;

    FLAC__stream_encoder_set_write_callback( p_sys->p_flac,
        EncoderWriteCallback );
    FLAC__stream_encoder_set_metadata_callback( p_sys->p_flac,
        EncoderMetadataCallback );
    FLAC__stream_encoder_set_client_data( p_sys->p_flac, p_enc );

    /* Get and store the STREAMINFO metadata block as a p_extra */
    p_sys->p_chain = 0;
    FLAC__stream_encoder_init( p_sys->p_flac );

    return VLC_SUCCESS;
}

/****************************************************************************
 * Encode: the whole thing
 ****************************************************************************
 * This function spits out ogg packets.
 ****************************************************************************/
static block_t *Encode( encoder_t *p_enc, aout_buffer_t *p_aout_buf )
{
    encoder_sys_t *p_sys = p_enc->p_sys;
    block_t *p_chain;
    int i;

    p_sys->i_pts = p_aout_buf->start_date -
                (mtime_t)1000000 * (mtime_t)p_sys->i_samples_delay /
                (mtime_t)p_enc->fmt_in.audio.i_rate;

    p_sys->i_samples_delay += p_aout_buf->i_nb_samples;

    /* Convert samples to FLAC__int32 */
    if( p_sys->i_buffer < p_aout_buf->i_nb_bytes * 2 )
    {
        p_sys->p_buffer =
            realloc( p_sys->p_buffer, p_aout_buf->i_nb_bytes * 2 );
        p_sys->i_buffer = p_aout_buf->i_nb_bytes * 2;
    }

    for( i = 0 ; i < p_aout_buf->i_nb_bytes / 2 ; i++ )
    {
        p_sys->p_buffer[i]= ((int16_t *)p_aout_buf->p_buffer)[i];
    }

    FLAC__stream_encoder_process_interleaved( p_sys->p_flac, p_sys->p_buffer,
                                              p_aout_buf->i_nb_samples );

    p_chain = p_sys->p_chain;
    p_sys->p_chain = 0;

    return p_chain;
}

/*****************************************************************************
 * CloseEncoder: encoder destruction
 *****************************************************************************/
static void CloseEncoder( vlc_object_t *p_this )
{
    encoder_t *p_enc = (encoder_t *)p_this;
    encoder_sys_t *p_sys = p_enc->p_sys;

    FLAC__stream_encoder_delete( p_sys->p_flac );

    if( p_sys->p_buffer ) free( p_sys->p_buffer );
    free( p_sys );
}

/*****************************************************************************
 * EncoderMetadataCallback: called by libflac to output metadata
 *****************************************************************************/
static void EncoderMetadataCallback( const FLAC__StreamEncoder *encoder,
                                     const FLAC__StreamMetadata *metadata,
                                     void *client_data )
{
    encoder_t *p_enc = (encoder_t *)client_data;

    msg_Err( p_enc, "MetadataCallback: %i", metadata->type );
    return;
}

/*****************************************************************************
 * EncoderWriteCallback: called by libflac to output encoded samples
 *****************************************************************************/
static FLAC__StreamEncoderWriteStatus
EncoderWriteCallback( const FLAC__StreamEncoder *encoder,
                      const FLAC__byte buffer[],
                      unsigned bytes, unsigned samples,
                      unsigned current_frame, void *client_data )
{
    encoder_t *p_enc = (encoder_t *)client_data;
    encoder_sys_t *p_sys = p_enc->p_sys;
    block_t *p_block;

    if( samples == 0 )
    {
        if( p_sys->i_headers == 1 )
        {
            msg_Dbg( p_enc, "Writing STREAMINFO: %i", bytes );

            /* Backup the STREAMINFO metadata block */
            p_enc->fmt_out.i_extra = STREAMINFO_SIZE + 4;
            p_enc->fmt_out.p_extra = malloc( STREAMINFO_SIZE + 4 );
            memcpy( p_enc->fmt_out.p_extra, "fLaC", 4 );
            memcpy( ((uint8_t *)p_enc->fmt_out.p_extra) + 4, buffer,
                    STREAMINFO_SIZE );

            /* Fake this as the last metadata block */
            ((uint8_t*)p_enc->fmt_out.p_extra)[4] |= 0x80;
        }
        p_sys->i_headers++;
        return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
    }

    p_block = block_New( p_enc, bytes );
    memcpy( p_block->p_buffer, buffer, bytes );

    p_block->i_dts = p_block->i_pts = p_sys->i_pts;

    p_sys->i_samples_delay -= samples;

    p_block->i_length = (mtime_t)1000000 *
        (mtime_t)samples / (mtime_t)p_enc->fmt_in.audio.i_rate;

    /* Update pts */
    p_sys->i_pts += p_block->i_length;

    block_ChainAppend( &p_sys->p_chain, p_block );

    return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}
#endif