adpcm.c

tcpmp播放器的flv插件

        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] = clip(*src++, 0, 7);
        block_predictor[1] = 0;
        if (st)
            block_predictor[1] = clip(*src++, 0, 7);
        c->status[0].idelta = (int16_t)((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
        src+=2;
        if (st){
            c->status[1].idelta = (int16_t)((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
            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 = (int16_t)(src[0] | (src[1] << 8));
        c->status[0].step_index = src[2];
        src += 4;
        *samples++ = c->status[0].predictor;
        if (st) {
            c->status[1].predictor = (int16_t)(src[0] | (src[1] << 8));
            c->status[1].step_index = src[2];
            src += 4;
            *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, 3);

            /* 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, 3);
            else
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F, 3);

            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 = (int16_t)(src[10] | (src[11] << 8));
        c->status[1].predictor = (int16_t)(src[12] | (src[13] << 8));
        c->status[0].step_index = src[14];
        c->status[1].step_index = src[15];
        /* sign extend the predictors */
        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, 3);

            /* process the diff channel predictor */
            DK3_GET_NEXT_NIBBLE();
            adpcm_ima_expand_nibble(&c->status[1], nibble, 3);

            /* 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, 3);

            /* 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, 3);
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
                    src[0] & 0x0F, 3);
            } else {
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F, 3);
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F, 3);
            }

            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;
    case CODEC_ID_ADPCM_EA:
        samples_in_chunk = LE_32(src);
        if (samples_in_chunk >= ((buf_size - 12) * 2)) {
            src += buf_size;
            break;
        }
        src += 4;
        current_left_sample = (int16_t)LE_16(src);
        src += 2;
        previous_left_sample = (int16_t)LE_16(src);
        src += 2;
        current_right_sample = (int16_t)LE_16(src);
        src += 2;
        previous_right_sample = (int16_t)LE_16(src);
        src += 2;

        for (count1 = 0; count1 < samples_in_chunk/28;count1++) {
            coeff1l = ea_adpcm_table[(*src >> 4) & 0x0F];
            coeff2l = ea_adpcm_table[((*src >> 4) & 0x0F) + 4];
            coeff1r = ea_adpcm_table[*src & 0x0F];
            coeff2r = ea_adpcm_table[(*src & 0x0F) + 4];
            src++;

            shift_left = ((*src >> 4) & 0x0F) + 8;
            shift_right = (*src & 0x0F) + 8;
            src++;

            for (count2 = 0; count2 < 28; count2++) {
                next_left_sample = (((*src & 0xF0) << 24) >> shift_left);
                next_right_sample = (((*src & 0x0F) << 28) >> shift_right);
                src++;

                next_left_sample = (next_left_sample + 
                    (current_left_sample * coeff1l) + 
                    (previous_left_sample * coeff2l) + 0x80) >> 8;
                next_right_sample = (next_right_sample + 
                    (current_right_sample * coeff1r) + 
                    (previous_right_sample * coeff2r) + 0x80) >> 8;
                CLAMP_TO_SHORT(next_left_sample);
                CLAMP_TO_SHORT(next_right_sample);

                previous_left_sample = current_left_sample;
                current_left_sample = next_left_sample;
                previous_right_sample = current_right_sample;
                current_right_sample = next_right_sample;
                *samples++ = (unsigned short)current_left_sample;
                *samples++ = (unsigned short)current_right_sample;
            }
        }
        break;
    case CODEC_ID_ADPCM_IMA_SMJPEG:
        c->status[0].predictor = *src;
        src += 2;
        c->status[0].step_index = *src++;
        src++;  /* skip another byte before getting to the meat */
        while (src < buf + buf_size) {
            *samples++ = adpcm_ima_expand_nibble(&c->status[0],
                *src & 0x0F, 3);
            *samples++ = adpcm_ima_expand_nibble(&c->status[0],
                (*src >> 4) & 0x0F, 3);
            src++;
        }
        break;
    case CODEC_ID_ADPCM_CT:
	while (src < buf + buf_size) {
            if (st) {
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F);
                *samples++ = adpcm_ct_expand_nibble(&c->status[1], 
                    src[0] & 0x0F);
            } else {
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F);
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    src[0] & 0x0F);
            }
	    src++;
        }
        break;
    case CODEC_ID_ADPCM_SWF:
    {
	GetBitContext gb;
	const int *table;
	int k0, signmask;
	int size = buf_size*8;
	
	init_get_bits(&gb, buf, size);

	// first frame, read bits & inital values
	if (!c->nb_bits)
	{
	    c->nb_bits = get_bits(&gb, 2)+2;
//	    av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", c->nb_bits);
	}
	
	table = swf_index_tables[c->nb_bits-2];
	k0 = 1 << (c->nb_bits-2);
	signmask = 1 << (c->nb_bits-1);
	
	while (get_bits_count(&gb) <= size)
	{
	    int i;

	    c->nb_samples++;
	    // wrap around at every 4096 samples...
	    if ((c->nb_samples & 0xfff) == 1)
	    {
		for (i = 0; i <= st; i++)
		{
		    *samples++ = c->status[i].predictor = get_sbits(&gb, 16);
		    c->status[i].step_index = get_bits(&gb, 6);
		}
	    }

	    // similar to IMA adpcm
	    for (i = 0; i <= st; i++)
	    {
		int delta = get_bits(&gb, c->nb_bits);
		int step = step_table[c->status[i].step_index];
		long vpdiff = 0; // vpdiff = (delta+0.5)*step/4
		int k = k0;
		
		do {
		    if (delta & k)
			vpdiff += step;
		    step >>= 1;
		    k >>= 1;
		} while(k);
		vpdiff += step;
		
		if (delta & signmask)
		    c->status[i].predictor -= vpdiff;
		else
		    c->status[i].predictor += vpdiff;
		
		c->status[i].step_index += table[delta & (~signmask)];
		
		c->status[i].step_index = clip(c->status[i].step_index, 0, 88);
		c->status[i].predictor = clip(c->status[i].predictor, -32768, 32767);
		
		*samples++ = c->status[i].predictor;
	    }
	}
	
//	src += get_bits_count(&gb)*8;
	src += size;
	
	break;
    }
    case CODEC_ID_ADPCM_YAMAHA:
        while (src < buf + buf_size) {
            if (st) {
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0],
                        src[0] & 0x0F);
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[1],
                        (src[0] >> 4) & 0x0F);
            } else {
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0],
                        src[0] & 0x0F);
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0],
                        (src[0] >> 4) & 0x0F);
            }
            src++;
        }
        break;
    default:
        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_IMA_SMJPEG, adpcm_ima_smjpeg);
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);
ADPCM_CODEC(CODEC_ID_ADPCM_EA, adpcm_ea);
ADPCM_CODEC(CODEC_ID_ADPCM_CT, adpcm_ct);
ADPCM_CODEC(CODEC_ID_ADPCM_SWF, adpcm_swf);
ADPCM_CODEC(CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha);

#undef ADPCM_CODEC