adpcm.c

tcpmp播放器的flv插件

            c->status[i].coeff2 = AdaptCoeff2[predictor];
        }
        for(i=0; i<avctx->channels; i++){
            if (c->status[i].idelta < 16) 
                c->status[i].idelta = 16;
            
            *dst++ = c->status[i].idelta & 0xFF;
            *dst++ = c->status[i].idelta >> 8;
        }
        for(i=0; i<avctx->channels; i++){
            c->status[i].sample1= *samples++;

            *dst++ = c->status[i].sample1 & 0xFF;
            *dst++ = c->status[i].sample1 >> 8;
        }
        for(i=0; i<avctx->channels; i++){
            c->status[i].sample2= *samples++;

            *dst++ = c->status[i].sample2 & 0xFF;
            *dst++ = c->status[i].sample2 >> 8;
        }

        for(i=7*avctx->channels; i<avctx->block_align; i++) {
            int nibble;
            nibble = adpcm_ms_compress_sample(&c->status[ 0], *samples++)<<4;
            nibble|= adpcm_ms_compress_sample(&c->status[st], *samples++);
            *dst++ = nibble;
        }
        break;
    case CODEC_ID_ADPCM_YAMAHA:
        n = avctx->frame_size / 2;
        for (; n>0; n--) {
            for(i = 0; i < avctx->channels; i++) {
                int nibble;
                nibble  = adpcm_yamaha_compress_sample(&c->status[i], samples[i]);
                nibble |= adpcm_yamaha_compress_sample(&c->status[i], samples[i+avctx->channels]) << 4;
                *dst++ = nibble;
            }
            samples += 2 * avctx->channels;
        }
        break;
    default:
        return -1;
    }
    return dst - frame;
}
#endif //CONFIG_ENCODERS

static int adpcm_decode_init(AVCodecContext * avctx)
{
    ADPCMContext *c = avctx->priv_data;

    c->channel = 0;
    c->status[0].predictor = c->status[1].predictor = 0;
    c->status[0].step_index = c->status[1].step_index = 0;
    c->status[0].step = c->status[1].step = 0;

    switch(avctx->codec->id) {
    case CODEC_ID_ADPCM_CT:
	c->status[0].step = c->status[1].step = 511;
	break;
    default:
        break;
    }
    return 0;
}

static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble, int shift)
{
    int step_index;
    int predictor;
    int sign, delta, diff, step;

    step = step_table[c->step_index];
    step_index = c->step_index + index_table[(unsigned)nibble];
    if (step_index < 0) step_index = 0;
    else if (step_index > 88) step_index = 88;

    sign = nibble & 8;
    delta = nibble & 7;
    /* perform direct multiplication instead of series of jumps proposed by
     * the reference ADPCM implementation since modern CPUs can do the mults
     * quickly enough */
    diff = ((2 * delta + 1) * step) >> shift;
    predictor = c->predictor;
    if (sign) predictor -= diff;
    else predictor += diff;

    CLAMP_TO_SHORT(predictor);
    c->predictor = predictor;
    c->step_index = step_index;

    return (short)predictor;
}

static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)
{
    int predictor;

    predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256;
    predictor += (signed)((nibble & 0x08)?(nibble - 0x10):(nibble)) * c->idelta;
    CLAMP_TO_SHORT(predictor);

    c->sample2 = c->sample1;
    c->sample1 = predictor;
    c->idelta = (AdaptationTable[(int)nibble] * c->idelta) >> 8;
    if (c->idelta < 16) c->idelta = 16;

    return (short)predictor;
}

static inline short adpcm_ct_expand_nibble(ADPCMChannelStatus *c, char nibble)
{
    int predictor;
    int sign, delta, diff;
    int new_step;

    sign = nibble & 8;
    delta = nibble & 7;
    /* perform direct multiplication instead of series of jumps proposed by
     * the reference ADPCM implementation since modern CPUs can do the mults
     * quickly enough */
    diff = ((2 * delta + 1) * c->step) >> 3;
    predictor = c->predictor;
    /* predictor update is not so trivial: predictor is multiplied on 254/256 before updating */
    if(sign)
	predictor = ((predictor * 254) >> 8) - diff;
    else
    	predictor = ((predictor * 254) >> 8) + diff;
    /* calculate new step and clamp it to range 511..32767 */
    new_step = (ct_adpcm_table[nibble & 7] * c->step) >> 8;
    c->step = new_step;
    if(c->step < 511)
	c->step = 511;
    if(c->step > 32767)
	c->step = 32767;

    CLAMP_TO_SHORT(predictor);
    c->predictor = predictor;
    return (short)predictor;
}

static inline short adpcm_yamaha_expand_nibble(ADPCMChannelStatus *c, unsigned char nibble)
{
    if(!c->step) {
        c->predictor = 0;
        c->step = 127;
    }

    c->predictor += (c->step * yamaha_difflookup[nibble]) / 8;
    CLAMP_TO_SHORT(c->predictor);
    c->step = (c->step * yamaha_indexscale[nibble]) >> 8;
    c->step = clip(c->step, 127, 24567);
    return c->predictor;
}

static void xa_decode(short *out, const unsigned char *in, 
    ADPCMChannelStatus *left, ADPCMChannelStatus *right, int inc)
{
    int i, j;
    int shift,filter,f0,f1;
    int s_1,s_2;
    int d,s,t;

    for(i=0;i<4;i++) {

        shift  = 12 - (in[4+i*2] & 15);
        filter = in[4+i*2] >> 4;
        f0 = xa_adpcm_table[filter][0];
        f1 = xa_adpcm_table[filter][1];

        s_1 = left->sample1;
        s_2 = left->sample2;

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

            t = (signed char)(d<<4)>>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 */
            left->sample1 = s_1;
            left->sample2 = s_2;
            s_1 = right->sample1;
            s_2 = right->sample2;
            out = out + 1 - 28*2;
        }

        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;

    /* EA ADPCM state variables */
    uint32_t samples_in_chunk;
    int32_t previous_left_sample, previous_right_sample;
    int32_t current_left_sample, current_right_sample;
    int32_t next_left_sample, next_right_sample;
    int32_t coeff1l, coeff2l, coeff1r, coeff2r;
    uint8_t shift_left, shift_right;
    int count1, count2;

    if (!buf_size)
        return 0;

    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++;

        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, 3);
            samples += avctx->channels;
            *samples = adpcm_ima_expand_nibble(cs, (src[0] >> 4) & 0x0F, 3);
            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 == 1) { /* wait for the other packet before outputing anything */
                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;

        for(i=0; i<avctx->channels; i++){
            cs = &(c->status[i]);
            cs->predictor = *src++;
            cs->predictor |= (*src++) << 8;
            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 */
        }

        for(m=4; src < (buf + buf_size);) {
	    *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[0] & 0x0F, 3);
            if (st)
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[4] & 0x0F, 3);
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F, 3);
	    if (st) {
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], (src[4] >> 4) & 0x0F, 3);
		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;
        for(i=0; i<m; i++) {
	    *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[i] & 0x0F, 4);
            if (st)
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[i+m] & 0x0F, 4);
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[i] >> 4, 4);
	    if (st)
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[i+m] >> 4, 4);
	}