adpcm.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

        shift  = 12 - (in[5+i*2] & 15);
        filter = in[5+i*2] >> 4;

        f0 = xa_adpcm_table[filter][0];
        f1 = xa_adpcm_table[filter][1];

        for(j=0;j<28;j++) {
            d = in[16+i+j*4];

            t = (signed char)d >> 4;
            s = ( t<<shift ) + ((s_1*f0 + s_2*f1+32)>>6);
            CLAMP_TO_SHORT(s);
            *out = s;
            out += inc;
            s_2 = s_1;
            s_1 = s;
        }

        if (inc==2) { /* stereo */
            right->sample1 = s_1;
            right->sample2 = s_2;
            out -= 1;
        } else {
            left->sample1 = s_1;
            left->sample2 = s_2;
        }
    }
}


/* DK3 ADPCM support macro */
#define DK3_GET_NEXT_NIBBLE() \
    if (decode_top_nibble_next) \
    { \
        nibble = (last_byte >> 4) & 0x0F; \
        decode_top_nibble_next = 0; \
    } \
    else \
    { \
        last_byte = *src++; \
        if (src >= buf + buf_size) break; \
        nibble = last_byte & 0x0F; \
        decode_top_nibble_next = 1; \
    }

static int adpcm_decode_frame(AVCodecContext *avctx,
			    void *data, int *data_size,
			    uint8_t *buf, int buf_size)
{
    ADPCMContext *c = avctx->priv_data;
    ADPCMChannelStatus *cs;
    int n, m, channel, i;
    int block_predictor[2];
    short *samples;
    uint8_t *src;
    int st; /* stereo */

    /* DK3 ADPCM accounting variables */
    unsigned char last_byte = 0;
    unsigned char nibble;
    int decode_top_nibble_next = 0;
    int diff_channel;

    samples = data;
    src = buf;

    st = avctx->channels == 2;

    switch(avctx->codec->id) {
    case CODEC_ID_ADPCM_IMA_QT:
        n = (buf_size - 2);/* >> 2*avctx->channels;*/
        channel = c->channel;
        cs = &(c->status[channel]);
        /* (pppppp) (piiiiiii) */

        /* Bits 15-7 are the _top_ 9 bits of the 16-bit initial predictor value */
        cs->predictor = (*src++) << 8;
        cs->predictor |= (*src & 0x80);
        cs->predictor &= 0xFF80;

        /* sign extension */
        if(cs->predictor & 0x8000)
            cs->predictor -= 0x10000;

        CLAMP_TO_SHORT(cs->predictor);

        cs->step_index = (*src++) & 0x7F;

        if (cs->step_index > 88) av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index);
        if (cs->step_index > 88) cs->step_index = 88;

        cs->step = step_table[cs->step_index];

        if (st && channel)
            samples++;

        *samples++ = cs->predictor;
        samples += st;

        for(m=32; n>0 && m>0; n--, m--) { /* in QuickTime, IMA is encoded by chuncks of 34 bytes (=64 samples) */
            *samples = adpcm_ima_expand_nibble(cs, src[0] & 0x0F);
            samples += avctx->channels;
            *samples = adpcm_ima_expand_nibble(cs, (src[0] >> 4) & 0x0F);
            samples += avctx->channels;
            src ++;
        }

        if(st) { /* handle stereo interlacing */
            c->channel = (channel + 1) % 2; /* we get one packet for left, then one for right data */
            if(channel == 0) { /* wait for the other packet before outputing anything */
                *data_size = 0;
                return src - buf;
            }
        }
        break;
    case CODEC_ID_ADPCM_IMA_WAV:
        if (avctx->block_align != 0 && buf_size > avctx->block_align)
            buf_size = avctx->block_align;

	// XXX: do as per-channel loop
        cs = &(c->status[0]);
        cs->predictor = (*src++) & 0x0FF;
        cs->predictor |= ((*src++) << 8) & 0x0FF00;
        if(cs->predictor & 0x8000)
            cs->predictor -= 0x10000;
        CLAMP_TO_SHORT(cs->predictor);

	// XXX: is this correct ??: *samples++ = cs->predictor;

	cs->step_index = *src++;
        if (cs->step_index < 0) cs->step_index = 0;
        if (cs->step_index > 88) cs->step_index = 88;
        if (*src++) av_log(avctx, AV_LOG_ERROR, "unused byte should be null !!\n"); /* unused */

        if (st) {
            cs = &(c->status[1]);
            cs->predictor = (*src++) & 0x0FF;
            cs->predictor |= ((*src++) << 8) & 0x0FF00;
            if(cs->predictor & 0x8000)
                cs->predictor -= 0x10000;
            CLAMP_TO_SHORT(cs->predictor);

	    // XXX: is this correct ??: *samples++ = cs->predictor;

	    cs->step_index = *src++;
            if (cs->step_index < 0) cs->step_index = 0;
            if (cs->step_index > 88) cs->step_index = 88;
            src++; /* if != 0  -> out-of-sync */
        }

        for(m=4; src < (buf + buf_size);) {
	    *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[0] & 0x0F);
            if (st)
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[4] & 0x0F);
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);
	    if (st) {
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], (src[4] >> 4) & 0x0F);
		if (!--m) {
		    m=4;
		    src+=4;
		}
	    }
	    src++;
	}
        break;
    case CODEC_ID_ADPCM_4XM:
        cs = &(c->status[0]);
        c->status[0].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
        if(st){
            c->status[1].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
        }
        c->status[0].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
        if(st){
            c->status[1].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
        }
//            if (cs->step_index < 0) cs->step_index = 0;
//            if (cs->step_index > 88) cs->step_index = 88;

        m= (buf_size - (src - buf))>>st;
//printf("%d %d %d %d\n", st, m, c->status[0].predictor, c->status[0].step_index);
        //FIXME / XXX decode chanels individual & interleave samples
        for(i=0; i<m; i++) {
	    *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] & 0x0F);
            if (st)
                *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] & 0x0F);
            *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] >> 4);
	    if (st)
                *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] >> 4);
	}

        src += m<<st;

        break;
    case CODEC_ID_ADPCM_MS:
        if (avctx->block_align != 0 && buf_size > avctx->block_align)
            buf_size = avctx->block_align;
        n = buf_size - 7 * avctx->channels;
        if (n < 0)
            return -1;
        block_predictor[0] = (*src++); /* should be bound */
        block_predictor[0] = (block_predictor[0] < 0)?(0):((block_predictor[0] > 7)?(7):(block_predictor[0]));
        block_predictor[1] = 0;
        if (st)
            block_predictor[1] = (*src++);
        block_predictor[1] = (block_predictor[1] < 0)?(0):((block_predictor[1] > 7)?(7):(block_predictor[1]));
        c->status[0].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        if (c->status[0].idelta & 0x08000)
            c->status[0].idelta -= 0x10000;
        src+=2;
        if (st)
            c->status[1].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        if (st && c->status[1].idelta & 0x08000)
            c->status[1].idelta |= 0xFFFF0000;
        if (st)
            src+=2;
        c->status[0].coeff1 = AdaptCoeff1[block_predictor[0]];
        c->status[0].coeff2 = AdaptCoeff2[block_predictor[0]];
        c->status[1].coeff1 = AdaptCoeff1[block_predictor[1]];
        c->status[1].coeff2 = AdaptCoeff2[block_predictor[1]];
        
        c->status[0].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        src+=2;
        if (st) c->status[1].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        if (st) src+=2;
        c->status[0].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        src+=2;
        if (st) c->status[1].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        if (st) src+=2;

        *samples++ = c->status[0].sample1;
        if (st) *samples++ = c->status[1].sample1;
        *samples++ = c->status[0].sample2;
        if (st) *samples++ = c->status[1].sample2;
        for(;n>0;n--) {
            *samples++ = adpcm_ms_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);
            *samples++ = adpcm_ms_expand_nibble(&c->status[st], src[0] & 0x0F);
            src ++;
        }
        break;
    case CODEC_ID_ADPCM_IMA_DK4:
        if (avctx->block_align != 0 && buf_size > avctx->block_align)
            buf_size = avctx->block_align;

        c->status[0].predictor = (src[0] | (src[1] << 8));
        c->status[0].step_index = src[2];
        src += 4;
        if(c->status[0].predictor & 0x8000)
            c->status[0].predictor -= 0x10000;
        *samples++ = c->status[0].predictor;
        if (st) {
            c->status[1].predictor = (src[0] | (src[1] << 8));
            c->status[1].step_index = src[2];
            src += 4;
            if(c->status[1].predictor & 0x8000)
                c->status[1].predictor -= 0x10000;
            *samples++ = c->status[1].predictor;
        }
        while (src < buf + buf_size) {

            /* take care of the top nibble (always left or mono channel) */
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                (src[0] >> 4) & 0x0F);

            /* take care of the bottom nibble, which is right sample for
             * stereo, or another mono sample */
            if (st)
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
                    src[0] & 0x0F);
            else
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F);

            src++;
        }
        break;
    case CODEC_ID_ADPCM_IMA_DK3:
        if (avctx->block_align != 0 && buf_size > avctx->block_align)
            buf_size = avctx->block_align;

        c->status[0].predictor = (src[10] | (src[11] << 8));
        c->status[1].predictor = (src[12] | (src[13] << 8));
        c->status[0].step_index = src[14];
        c->status[1].step_index = src[15];
        /* sign extend the predictors */
        if(c->status[0].predictor & 0x8000)
            c->status[0].predictor -= 0x10000;
        if(c->status[1].predictor & 0x8000)
            c->status[1].predictor -= 0x10000;
        src += 16;
        diff_channel = c->status[1].predictor;

        /* the DK3_GET_NEXT_NIBBLE macro issues the break statement when
         * the buffer is consumed */
        while (1) {

            /* for this algorithm, c->status[0] is the sum channel and
             * c->status[1] is the diff channel */

            /* process the first predictor of the sum channel */
            DK3_GET_NEXT_NIBBLE();
            adpcm_ima_expand_nibble(&c->status[0], nibble);

            /* process the diff channel predictor */
            DK3_GET_NEXT_NIBBLE();
            adpcm_ima_expand_nibble(&c->status[1], nibble);

            /* process the first pair of stereo PCM samples */
            diff_channel = (diff_channel + c->status[1].predictor) / 2;
            *samples++ = c->status[0].predictor + c->status[1].predictor;
            *samples++ = c->status[0].predictor - c->status[1].predictor;

            /* process the second predictor of the sum channel */
            DK3_GET_NEXT_NIBBLE();
            adpcm_ima_expand_nibble(&c->status[0], nibble);

            /* process the second pair of stereo PCM samples */
            diff_channel = (diff_channel + c->status[1].predictor) / 2;
            *samples++ = c->status[0].predictor + c->status[1].predictor;
            *samples++ = c->status[0].predictor - c->status[1].predictor;
        }
        break;
    case CODEC_ID_ADPCM_IMA_WS:
        /* no per-block initialization; just start decoding the data */
        while (src < buf + buf_size) {

            if (st) {
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F);
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
                    src[0] & 0x0F);
            } else {
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F);
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F);
            }

            src++;
        }
        break;
    case CODEC_ID_ADPCM_XA:
        c->status[0].sample1 = c->status[0].sample2 = 
        c->status[1].sample1 = c->status[1].sample2 = 0;
        while (buf_size >= 128) {
            xa_decode(samples, src, &c->status[0], &c->status[1], 
                avctx->channels);
            src += 128;
            samples += 28 * 8;
            buf_size -= 128;
        }
        break;
    default:
        *data_size = 0;
        return -1;
    }
    *data_size = (uint8_t *)samples - (uint8_t *)data;
    return src - buf;
}



#ifdef CONFIG_ENCODERS
#define ADPCM_ENCODER(id,name)                  \
AVCodec name ## _encoder = {                    \
    #name,                                      \
    CODEC_TYPE_AUDIO,                           \
    id,                                         \
    sizeof(ADPCMContext),                       \
    adpcm_encode_init,                          \
    adpcm_encode_frame,                         \
    adpcm_encode_close,                         \
    NULL,                                       \
};
#else
#define ADPCM_ENCODER(id,name)
#endif

#ifdef CONFIG_DECODERS
#define ADPCM_DECODER(id,name)                  \
AVCodec name ## _decoder = {                    \
    #name,                                      \
    CODEC_TYPE_AUDIO,                           \
    id,                                         \
    sizeof(ADPCMContext),                       \
    adpcm_decode_init,                          \
    NULL,                                       \
    NULL,                                       \
    adpcm_decode_frame,                         \
};
#else
#define ADPCM_DECODER(id,name)
#endif

#define ADPCM_CODEC(id, name)                   \
ADPCM_ENCODER(id,name) ADPCM_DECODER(id,name)

ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WS, adpcm_ima_ws);
ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
ADPCM_CODEC(CODEC_ID_ADPCM_XA, adpcm_xa);
ADPCM_CODEC(CODEC_ID_ADPCM_ADX, adpcm_adx);

#undef ADPCM_CODEC