adpcm.c

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        }
        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 = AV_RL32(src);
        if (samples_in_chunk >= ((buf_size - 12) * 2)) {
            src += buf_size;
            break;
        }
        src += 4;
        current_left_sample = (int16_t)AV_RL16(src);
        src += 2;
        previous_left_sample = (int16_t)AV_RL16(src);
        src += 2;
        current_right_sample = (int16_t)AV_RL16(src);
        src += 2;
        previous_right_sample = (int16_t)AV_RL16(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;

                previous_left_sample = current_left_sample;
                current_left_sample = av_clip_int16(next_left_sample);
                previous_right_sample = current_right_sample;
                current_right_sample = av_clip_int16(next_right_sample);
                *samples++ = (unsigned short)current_left_sample;
                *samples++ = (unsigned short)current_right_sample;
            }
        }
        break;
    case CODEC_ID_ADPCM_IMA_AMV:
    case CODEC_ID_ADPCM_IMA_SMJPEG:
        c->status[0].predictor = (int16_t)bytestream_get_le16(&src);
        c->status[0].step_index = bytestream_get_le16(&src);

        if (avctx->codec->id == CODEC_ID_ADPCM_IMA_AMV)
            src+=4;

        while (src < buf + buf_size) {
            char hi, lo;
            lo = *src & 0x0F;
            hi = (*src >> 4) & 0x0F;

            if (avctx->codec->id == CODEC_ID_ADPCM_IMA_AMV)
                FFSWAP(char, hi, lo);

            *samples++ = adpcm_ima_expand_nibble(&c->status[0],
                lo, 3);
            *samples++ = adpcm_ima_expand_nibble(&c->status[0],
                hi, 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_SBPRO_4:
    case CODEC_ID_ADPCM_SBPRO_3:
    case CODEC_ID_ADPCM_SBPRO_2:
        if (!c->status[0].step_index) {
            /* the first byte is a raw sample */
            *samples++ = 128 * (*src++ - 0x80);
            if (st)
              *samples++ = 128 * (*src++ - 0x80);
            c->status[0].step_index = 1;
        }
        if (avctx->codec->id == CODEC_ID_ADPCM_SBPRO_4) {
            while (src < buf + buf_size) {
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    (src[0] >> 4) & 0x0F, 4, 0);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st],
                    src[0] & 0x0F, 4, 0);
                src++;
            }
        } else if (avctx->codec->id == CODEC_ID_ADPCM_SBPRO_3) {
            while (src < buf + buf_size && samples + 2 < samples_end) {
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    (src[0] >> 5) & 0x07, 3, 0);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    (src[0] >> 2) & 0x07, 3, 0);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    src[0] & 0x03, 2, 0);
                src++;
            }
        } else {
            while (src < buf + buf_size && samples + 3 < samples_end) {
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    (src[0] >> 6) & 0x03, 2, 2);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st],
                    (src[0] >> 4) & 0x03, 2, 2);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0],
                    (src[0] >> 2) & 0x03, 2, 2);
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st],
                    src[0] & 0x03, 2, 2);
                src++;
            }
        }
        break;
    case CODEC_ID_ADPCM_SWF:
    {
        GetBitContext gb;
        const int *table;
        int k0, signmask, nb_bits, count;
        int size = buf_size*8;

        init_get_bits(&gb, buf, size);

        //read bits & initial values
        nb_bits = get_bits(&gb, 2)+2;
        //av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", nb_bits);
        table = swf_index_tables[nb_bits-2];
        k0 = 1 << (nb_bits-2);
        signmask = 1 << (nb_bits-1);

        while (get_bits_count(&gb) <= size - 22*avctx->channels) {
            for (i = 0; i < avctx->channels; i++) {
                *samples++ = c->status[i].predictor = get_sbits(&gb, 16);
                c->status[i].step_index = get_bits(&gb, 6);
            }

            for (count = 0; get_bits_count(&gb) <= size - nb_bits*avctx->channels && count < 4095; count++) {
                int i;

                for (i = 0; i < avctx->channels; i++) {
                    // similar to IMA adpcm
                    int delta = get_bits(&gb, 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 = av_clip(c->status[i].step_index, 0, 88);
                    c->status[i].predictor = av_clip_int16(c->status[i].predictor);

                    *samples++ = c->status[i].predictor;
                    if (samples >= samples_end) {
                        av_log(avctx, AV_LOG_ERROR, "allocated output buffer is too small\n");
                        return -1;
                    }
                }
            }
        }
        src += buf_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;
    case CODEC_ID_ADPCM_THP:
    {
        int table[2][16];
        unsigned int samplecnt;
        int prev[2][2];
        int ch;

        if (buf_size < 80) {
            av_log(avctx, AV_LOG_ERROR, "frame too small\n");
            return -1;
        }

        src+=4;
        samplecnt = bytestream_get_be32(&src);

        for (i = 0; i < 32; i++)
            table[0][i] = (int16_t)bytestream_get_be16(&src);

        /* Initialize the previous sample.  */
        for (i = 0; i < 4; i++)
            prev[0][i] = (int16_t)bytestream_get_be16(&src);

        if (samplecnt >= (samples_end - samples) /  (st + 1)) {
            av_log(avctx, AV_LOG_ERROR, "allocated output buffer is too small\n");
            return -1;
        }

        for (ch = 0; ch <= st; ch++) {
            samples = (unsigned short *) data + ch;

            /* Read in every sample for this channel.  */
            for (i = 0; i < samplecnt / 14; i++) {
                int index = (*src >> 4) & 7;
                unsigned int exp = 28 - (*src++ & 15);
                int factor1 = table[ch][index * 2];
                int factor2 = table[ch][index * 2 + 1];

                /* Decode 14 samples.  */
                for (n = 0; n < 14; n++) {
                    int32_t sampledat;
                    if(n&1) sampledat=  *src++    <<28;
                    else    sampledat= (*src&0xF0)<<24;

                    sampledat = ((prev[ch][0]*factor1
                                + prev[ch][1]*factor2) >> 11) + (sampledat>>exp);
                    *samples = av_clip_int16(sampledat);
                    prev[ch][1] = prev[ch][0];
                    prev[ch][0] = *samples++;

                    /* In case of stereo, skip one sample, this sample
                       is for the other channel.  */
                    samples += st;
                }
            }
        }

        /* In the previous loop, in case stereo is used, samples is
           increased exactly one time too often.  */
        samples -= st;
        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_4XM, adpcm_4xm);
ADPCM_CODEC(CODEC_ID_ADPCM_CT, adpcm_ct);
ADPCM_CODEC(CODEC_ID_ADPCM_EA, adpcm_ea);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_AMV, adpcm_ima_amv);
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_QT, adpcm_ima_qt);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_SMJPEG, adpcm_ima_smjpeg);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WS, adpcm_ima_ws);
ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_4, adpcm_sbpro_4);
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_3, adpcm_sbpro_3);
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_2, adpcm_sbpro_2);
ADPCM_CODEC(CODEC_ID_ADPCM_SWF, adpcm_swf);
ADPCM_CODEC(CODEC_ID_ADPCM_THP, adpcm_thp);
ADPCM_CODEC(CODEC_ID_ADPCM_XA, adpcm_xa);
ADPCM_CODEC(CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha);

#undef ADPCM_CODEC