146 lines
5.0 KiB
C
146 lines
5.0 KiB
C
/**
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*@brief Uninitialize the decoder and free all resources.
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*@param avctx codec context
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*@return 0 on success, < 0 otherwise
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*/
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static av_cold int decode_end(AVCodecContext *avctx)
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{
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WMA3DecodeContext *s = avctx->priv_data;
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int i;
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av_freep(&s->num_sfb);
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av_freep(&s->sfb_offsets);
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av_freep(&s->subwoofer_cutoffs);
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av_freep(&s->sf_offsets);
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for (i = 0 ; i < WMAPRO_BLOCK_SIZES ; i++)
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ff_mdct_end(&s->mdct_ctx[i]);
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return 0;
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}
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/**
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*@brief Calculate a decorrelation matrix from the bitstream parameters.
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*@param s codec context
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*@param chgroup channel group for which the matrix needs to be calculated
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*/
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static void decode_decorrelation_matrix(WMA3DecodeContext *s,
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WMA3ChannelGroup *chgroup)
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{
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int i;
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int offset = 0;
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int8_t rotation_offset[WMAPRO_MAX_CHANNELS * WMAPRO_MAX_CHANNELS];
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memset(chgroup->decorrelation_matrix,0,
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sizeof(float) *s->num_channels * s->num_channels);
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for (i = 0; i < chgroup->num_channels * (chgroup->num_channels - 1) >> 1; i++)
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rotation_offset[i] = get_bits(&s->gb,6);
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for (i = 0; i < chgroup->num_channels; i++)
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chgroup->decorrelation_matrix[chgroup->num_channels * i + i] =
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get_bits1(&s->gb) ? 1.0 : -1.0;
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for (i = 1; i < chgroup->num_channels; i++) {
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int x;
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for (x = 0; x < i; x++) {
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int y;
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for (y = 0; y < i + 1 ; y++) {
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float v1 = chgroup->decorrelation_matrix[x * chgroup->num_channels + y];
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float v2 = chgroup->decorrelation_matrix[i * chgroup->num_channels + y];
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int n = rotation_offset[offset + x];
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float sinv;
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float cosv;
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if (n < 32) {
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sinv = sin64[n];
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cosv = sin64[32-n];
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} else {
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sinv = sin64[64-n];
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cosv = -sin64[n-32];
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}
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chgroup->decorrelation_matrix[y + x * chgroup->num_channels] =
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(v1 * sinv) - (v2 * cosv);
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chgroup->decorrelation_matrix[y + i * chgroup->num_channels] =
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(v1 * cosv) + (v2 * sinv);
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}
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}
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offset += i;
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}
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}
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/**
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*@brief Reconstruct the individual channel data.
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*@param s codec context
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*/
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static void inverse_channel_transform(WMA3DecodeContext *s)
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{
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int i;
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for (i = 0; i < s->num_chgroups; i++) {
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if (s->chgroup[i].transform == 1) {
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/** M/S stereo decoding */
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int16_t* sfb_offsets = s->cur_sfb_offsets;
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float* ch0 = *sfb_offsets + s->channel[0].coeffs;
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float* ch1 = *sfb_offsets++ + s->channel[1].coeffs;
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const char* tb = s->chgroup[i].transform_band;
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const char* tb_end = tb + s->num_bands;
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while (tb < tb_end) {
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const float* ch0_end = s->channel[0].coeffs +
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FFMIN(*sfb_offsets,s->subframe_len);
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if (*tb++ == 1) {
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while (ch0 < ch0_end) {
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const float v1 = *ch0;
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const float v2 = *ch1;
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*ch0++ = v1 - v2;
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*ch1++ = v1 + v2;
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}
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} else {
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while (ch0 < ch0_end) {
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*ch0++ *= 181.0 / 128;
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*ch1++ *= 181.0 / 128;
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}
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}
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++sfb_offsets;
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}
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} else if (s->chgroup[i].transform) {
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float data[WMAPRO_MAX_CHANNELS];
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const int num_channels = s->chgroup[i].num_channels;
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float** ch_data = s->chgroup[i].channel_data;
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float** ch_end = ch_data + num_channels;
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const int8_t* tb = s->chgroup[i].transform_band;
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int16_t* sfb;
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/** multichannel decorrelation */
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for (sfb = s->cur_sfb_offsets ;
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sfb < s->cur_sfb_offsets + s->num_bands;sfb++) {
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if (*tb++ == 1) {
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int y;
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/** multiply values with the decorrelation_matrix */
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for (y = sfb[0]; y < FFMIN(sfb[1], s->subframe_len); y++) {
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const float* mat = s->chgroup[i].decorrelation_matrix;
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const float* data_end = data + num_channels;
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float* data_ptr = data;
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float** ch;
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for (ch = ch_data;ch < ch_end; ch++)
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*data_ptr++ = (*ch)[y];
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for (ch = ch_data; ch < ch_end; ch++) {
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float sum = 0;
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data_ptr = data;
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while (data_ptr < data_end)
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sum += *data_ptr++ * *mat++;
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(*ch)[y] = sum;
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}
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}
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}
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}
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}
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}
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}
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