rockbox/apps/codecs/aiff.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (c) 2005 Jvo Studer
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include "codeclib.h"
#include <inttypes.h>

CODEC_HEADER

/* Macro that sign extends an unsigned byte */
#define SE(x) ((int32_t)((int8_t)(x)))

/* This codec supports AIFF files with the following formats:
 * - PCM, 8, 16 and 24 bits, mono or stereo
 */

enum
{
    AIFF_FORMAT_PCM = 0x0001,   /* AIFF PCM Format (big endian) */
    IEEE_FORMAT_FLOAT = 0x0003, /* IEEE Float */
    AIFF_FORMAT_ALAW = 0x0004,  /* AIFC ALaw compressed */
    AIFF_FORMAT_ULAW = 0x0005   /* AIFC uLaw compressed */
};

/* Maximum number of bytes to process in one iteration */
/* for 44.1kHz stereo 16bits, this represents 0.023s ~= 1/50s */
#define AIF_CHUNK_SIZE (1024*2)

static int32_t samples[AIF_CHUNK_SIZE] IBSS_ATTR;

enum codec_status codec_main(void)
{
    uint32_t numbytes, bytesdone;
    uint16_t num_channels = 0;
    uint32_t num_sample_frames = 0;
    uint16_t sample_size = 0;
    uint32_t sample_rate = 0;
    uint32_t i;
    size_t n;
    int bufcount;
    int endofstream;
    unsigned char *buf;
    uint8_t *aifbuf;
    long chunksize;
    uint32_t offset2snd = 0;
    uint16_t block_size = 0;
    uint32_t avgbytespersec = 0;
    off_t firstblockposn;     /* position of the first block in file */

    /* Generic codec initialisation */
    ci->configure(DSP_SET_SAMPLE_DEPTH, 28);
    ci->configure(CODEC_SET_FILEBUF_WATERMARK, 1024*512);
    ci->configure(CODEC_SET_FILEBUF_CHUNKSIZE, 1024*256);
  
next_track:
    if (codec_init()) {
        i = CODEC_ERROR;
        goto exit;
    }

    while (!*ci->taginfo_ready)
        ci->yield();
    
    /* assume the AIFF header is less than 1024 bytes */
    buf = ci->request_buffer(&n, 1024);
    if (n < 54) {
        i = CODEC_ERROR;
        goto done;
    }
    if ((memcmp(buf, "FORM", 4) != 0) || (memcmp(&buf[8], "AIFF", 4) != 0)) {
        i = CODEC_ERROR;
        goto done;
    }

    buf += 12;
    n -= 12;
    numbytes = 0;

    /* read until 'SSND' chunk, which typically is last */
    while (numbytes == 0 && n >= 8) {
        /* chunkSize */
        i = ((buf[4]<<24)|(buf[5]<<16)|(buf[6]<<8)|buf[7]);
        if (memcmp(buf, "COMM", 4) == 0) {
            if (i != 18) {
                DEBUGF("CODEC_ERROR: 'COMM' chunk size=%lu != 18\n", i);
                i = CODEC_ERROR;
                goto done;
            }
            /* num_channels */
            num_channels = ((buf[8]<<8)|buf[9]);
            /* num_sample_frames */
            num_sample_frames = ((buf[10]<<24)|(buf[11]<<16)|(buf[12]<<8)
                                |buf[13]);
            /* sample_size */
            sample_size  = ((buf[14]<<8)|buf[15]);
            /* sample_rate (don't use last 4 bytes, only integer fs) */
            if (buf[16] != 0x40) {
                DEBUGF("CODEC_ERROR: weird sampling rate (no @)\n", i);
                i = CODEC_ERROR;
                goto done;
            }
            sample_rate = ((buf[18]<<24)|(buf[19]<<16)|(buf[20]<<8)|buf[21])+1;
            sample_rate = sample_rate >> (16 + 14 - buf[17]);
            /* calc average bytes per second */
            avgbytespersec = sample_rate*num_channels*sample_size/8;
        } else if (memcmp(buf, "SSND", 4)==0) {
            if (sample_size == 0) {
                DEBUGF("CODEC_ERROR: unsupported chunk order\n");
                i = CODEC_ERROR;
                goto done;
            }
            /* offset2snd */
            offset2snd = (buf[8]<<24)|(buf[9]<<16)|(buf[10]<<8)|buf[11];
            /* block_size */
            block_size = (buf[12]<<24)|(buf[13]<<16)|(buf[14]<<8)|buf[15];
            if (block_size == 0)
                block_size = num_channels*sample_size;
            numbytes = i - 8 - offset2snd;
            i = 8 + offset2snd; /* advance to the beginning of data */
        } else {
            DEBUGF("unsupported AIFF chunk: '%c%c%c%c', size=%lu\n",
                   buf[0], buf[1], buf[2], buf[3], i);
        }

        if (i & 0x01) /* odd chunk sizes must be padded */
            i++;
        buf += i + 8;
        if (n < (i + 8)) {
            DEBUGF("CODEC_ERROR: AIFF header size > 1024\n");
            i = CODEC_ERROR;
            goto done;
        }
        n -= i + 8;
    } /* while 'SSND' */

    if (num_channels == 0) {
        DEBUGF("CODEC_ERROR: 'COMM' chunk not found or 0-channels file\n");
        i = CODEC_ERROR;
        goto done;
    }
    if (numbytes == 0) {
        DEBUGF("CODEC_ERROR: 'SSND' chunk not found or has zero length\n");
        i = CODEC_ERROR;
        goto done;
    }
    if (sample_size > 24) {
        DEBUGF("CODEC_ERROR: PCM with more than 24 bits per sample "
               "is unsupported\n");
        i = CODEC_ERROR;
        goto done;
    }

    ci->configure(DSP_SWITCH_FREQUENCY, ci->id3->frequency);

    if (num_channels == 2) {
        ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
    } else if (num_channels == 1) {
        ci->configure(DSP_SET_STEREO_MODE, STEREO_MONO);
    } else {
        DEBUGF("CODEC_ERROR: more than 2 channels unsupported\n");
        i = CODEC_ERROR;
        goto done;
    }

    firstblockposn = 1024 - n;
    ci->advance_buffer(firstblockposn);

    /* The main decoder loop */
    bytesdone = 0;
    ci->set_elapsed(0);
    endofstream = 0;
    /* chunksize is computed so that one chunk is about 1/50s.
     * this make 4096 for 44.1kHz 16bits stereo.
     * It also has to be a multiple of blockalign */
    chunksize = (1 + avgbytespersec/(50*block_size))*block_size;
    /* check that the output buffer is big enough (convert to samplespersec,
      then round to the block_size multiple below) */
    if (((uint64_t)chunksize*ci->id3->frequency*num_channels*2)
        /(uint64_t)avgbytespersec >= AIF_CHUNK_SIZE) {
        chunksize = ((uint64_t)AIF_CHUNK_SIZE*avgbytespersec
                     /((uint64_t)ci->id3->frequency*num_channels*2 
                     *block_size))*block_size;
    }

    while (!endofstream) {
        ci->yield();
        if (ci->stop_codec || ci->new_track)
            break;

        if (ci->seek_time) {
            uint32_t newpos;

            /* use avgbytespersec to round to the closest blockalign multiple,
               add firstblockposn. 64-bit casts to avoid overflows. */
            newpos = (((uint64_t)avgbytespersec*(ci->seek_time - 1))
                      /(1000LL*block_size))*block_size;
            if (newpos > numbytes)
                break;
            if (ci->seek_buffer(firstblockposn + newpos))
                bytesdone = newpos;
            ci->seek_complete();
        }
        aifbuf = (uint8_t *)ci->request_buffer(&n, chunksize);

        if (n == 0)
            break; /* End of stream */

        if (bytesdone + n > numbytes) {
            n = numbytes - bytesdone;
            endofstream = 1;
        }

        if (sample_size > 24) {
            for (i = 0; i < n; i += 4) {
                samples[i/4] = (SE(aifbuf[i])<<21)|(aifbuf[i + 1]<<13)
                               |(aifbuf[i + 2]<<5)|(aifbuf[i + 3]>>3);
            }
            bufcount = n >> 2;
        } else if (sample_size > 16) {
            for (i = 0; i < n; i += 3) {
                samples[i/3] = (SE(aifbuf[i])<<21)|(aifbuf[i + 1]<<13)
                               |(aifbuf[i + 2]<<5);
            }
            bufcount = n/3;
        } else if (sample_size > 8) {
            for (i = 0; i < n; i += 2)
                samples[i/2] = (SE(aifbuf[i])<<21)|(aifbuf[i + 1]<<13);
            bufcount = n >> 1;
        } else {
            for (i = 0; i < n; i++)
                samples[i] = SE(aifbuf[i]) << 21;
            bufcount = n;
        }

        if (num_channels == 2)
            bufcount >>= 1;

        ci->pcmbuf_insert(samples, NULL, bufcount);

        ci->advance_buffer(n);
        bytesdone += n;
        if (bytesdone >= numbytes)
            endofstream = 1;

        ci->set_elapsed(bytesdone*1000LL/avgbytespersec);
    }
    i = CODEC_OK;

done:
    if (ci->request_next_track())
        goto next_track;

exit:
    return i;
}