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avcodec/mlpenc: fix stereo decorrelation
This commit is contained in:
Paul B Mahol
parent
12c4cf9f72
commit
27c623b3d5
@ -645,6 +645,8 @@ static av_cold int mlp_encode_init(AVCodecContext *avctx)
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/* FIXME: this works for 1 and 2 channels, but check for more */
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rh->max_matrix_channel = rh->max_channel;
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ctx->number_of_samples = avctx->frame_size * MAJOR_HEADER_INTERVAL;
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if ((ret = ff_lpc_init(&ctx->lpc_ctx, ctx->number_of_samples,
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MLP_MAX_LPC_ORDER, ctx->lpc_type)) < 0)
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return ret;
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@ -1211,9 +1213,9 @@ static void input_to_sample_buffer(MLPEncodeContext *ctx)
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****************************************************************************/
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/** Counts the number of trailing zeroes in a value */
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static int number_trailing_zeroes(int32_t sample)
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static int number_trailing_zeroes(int32_t sample, unsigned int max, unsigned int def)
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{
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return sample ? FFMIN(15, ff_ctz(sample)) : 0;
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return sample ? FFMIN(max, ff_ctz(sample)) : def;
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}
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/** Determines how many bits are zero at the end of all samples so they can be
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@ -1237,7 +1239,7 @@ static void determine_quant_step_size(MLPEncodeContext *ctx)
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}
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for (unsigned int channel = 0; channel <= rh->max_channel; channel++)
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dp->quant_step_size[channel] = number_trailing_zeroes(sample_mask[channel]) - mp->shift[channel];
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dp->quant_step_size[channel] = number_trailing_zeroes(sample_mask[channel], 15, 0) - mp->shift[channel];
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}
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/** Determines the smallest number of bits needed to encode the filter
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@ -1322,41 +1324,74 @@ static void determine_filters(MLPEncodeContext *ctx)
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}
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}
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enum MLPChMode {
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MLP_CHMODE_LEFT_RIGHT,
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MLP_CHMODE_LEFT_SIDE,
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MLP_CHMODE_RIGHT_SIDE,
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MLP_CHMODE_MID_SIDE,
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};
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static enum MLPChMode estimate_stereo_mode(MLPEncodeContext *ctx)
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static int estimate_coeff(MLPEncodeContext *ctx,
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MatrixParams *mp,
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unsigned int ch0, unsigned int ch1)
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{
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uint64_t score[4], sum[4] = { 0, 0, 0, 0, };
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int32_t *right_ch = ctx->sample_buffer + 1;
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int32_t *left_ch = ctx->sample_buffer;
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int i;
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enum MLPChMode best = 0;
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const int number_of_samples = ctx->number_of_samples;
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const int num_channels = ctx->num_channels;
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int first = 1, x, x0;
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const int32_t *ch[2];
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int64_t g = 0, g0 = 0;
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for(i = 2; i < ctx->number_of_samples; i++) {
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int32_t left = left_ch [i * ctx->num_channels] - 2 * left_ch [(i - 1) * ctx->num_channels] + left_ch [(i - 2) * ctx->num_channels];
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int32_t right = right_ch[i * ctx->num_channels] - 2 * right_ch[(i - 1) * ctx->num_channels] + right_ch[(i - 2) * ctx->num_channels];
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ch[0] = ctx->sample_buffer + ch0;
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ch[1] = ctx->sample_buffer + ch1;
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sum[0] += FFABS( left );
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sum[1] += FFABS( right);
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sum[2] += FFABS((left + right) >> 1);
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sum[3] += FFABS( left - right);
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for (int n = 0, i = 0; n < number_of_samples; n++) {
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int64_t c0, c1;
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int32_t a0, a1;
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c0 = ch[0][i];
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c1 = ch[1][i];
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if (!c0 && !c1)
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goto next;
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if (!c0 || !c1) {
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g0 = 0;
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break;
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}
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a0 = FFABS(c0);
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a1 = FFABS(c1);
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if (a0 >= a1) {
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g = (c1 * (1 << 14)) / c0;
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x = ch1;
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} else if (a0 < a1) {
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g = (c0 * (1 << 14)) / c1;
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x = ch0;
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}
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if (first) {
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g0 = g;
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x0 = x;
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first = 0;
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} else if (g != g0 || x != x0) {
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g0 = 0;
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break;
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}
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next:
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i += num_channels;
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}
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score[MLP_CHMODE_LEFT_RIGHT] = sum[0] + sum[1];
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score[MLP_CHMODE_LEFT_SIDE] = sum[0] + sum[3];
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score[MLP_CHMODE_RIGHT_SIDE] = sum[1] + sum[3];
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score[MLP_CHMODE_MID_SIDE] = sum[2] + sum[3];
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if (g0) {
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mp->outch[0] = (x0 == ch0) ? ch0 : ch1;
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for(i = 1; i < 3; i++)
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if(score[i] < score[best])
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best = i;
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mp->coeff[0][ch0] = (x0 == ch1) ? g0 : 0;
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mp->coeff[0][ch1] = (x0 == ch0) ? g0 : 0;
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return best;
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mp->forco[0][ch0] = 0;
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mp->forco[0][ch1] = 0;
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mp->coeff[0][num_channels - 2] = mp->coeff[0][num_channels - 1] = 0;
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mp->forco[0][num_channels - 2] = mp->forco[0][num_channels - 1] = 0;
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return 1;
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}
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return 0;
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}
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/** Determines how many fractional bits are needed to encode matrix
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@ -1367,16 +1402,12 @@ static void code_matrix_coeffs(MLPEncodeContext *ctx, unsigned int mat)
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DecodingParams *dp = ctx->cur_decoding_params;
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MatrixParams *mp = &dp->matrix_params;
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int32_t coeff_mask = 0;
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unsigned int bits;
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for (unsigned int channel = 0; channel < ctx->num_channels; channel++) {
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int32_t coeff = mp->coeff[mat][channel];
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coeff_mask |= coeff;
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coeff_mask |= mp->coeff[mat][channel];
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}
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for (bits = 0; bits < 14 && !(coeff_mask & (1<<bits)); bits++);
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mp->fbits [mat] = 14 - bits;
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mp->fbits[mat] = 14 - number_trailing_zeroes(coeff_mask, 14, 14);
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}
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/** Determines best coefficients to use for the lossless matrix. */
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@ -1385,38 +1416,12 @@ static void lossless_matrix_coeffs(MLPEncodeContext *ctx)
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DecodingParams *dp = ctx->cur_decoding_params;
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MatrixParams *mp = &dp->matrix_params;
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unsigned int shift = 0;
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enum MLPChMode mode;
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if (1 || ctx->num_channels - 2 != 2) {
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mp->count = 0;
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mp->count = 0;
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if (ctx->num_channels - 2 != 2)
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return;
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}
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mode = estimate_stereo_mode(ctx);
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switch (mode) {
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/* TODO: add matrix for MID_SIDE */
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case MLP_CHMODE_MID_SIDE:
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case MLP_CHMODE_LEFT_RIGHT:
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mp->count = 0;
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break;
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case MLP_CHMODE_LEFT_SIDE:
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mp->count = 1;
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mp->outch[0] = 1;
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mp->coeff[0][0] = 1 << 14; mp->coeff[0][1] = -(1 << 14);
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mp->coeff[0][2] = 0 << 14; mp->coeff[0][2] = 0 << 14;
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mp->forco[0][0] = 1 << 14; mp->forco[0][1] = -(1 << 14);
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mp->forco[0][2] = 0 << 14; mp->forco[0][2] = 0 << 14;
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break;
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case MLP_CHMODE_RIGHT_SIDE:
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mp->count = 1;
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mp->outch[0] = 0;
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mp->coeff[0][0] = 1 << 14; mp->coeff[0][1] = 1 << 14;
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mp->coeff[0][2] = 0 << 14; mp->coeff[0][2] = 0 << 14;
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mp->forco[0][0] = 1 << 14; mp->forco[0][1] = -(1 << 14);
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mp->forco[0][2] = 0 << 14; mp->forco[0][2] = 0 << 14;
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break;
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}
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mp->count = estimate_coeff(ctx, mp, 0, 1);
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for (int mat = 0; mat < mp->count; mat++)
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code_matrix_coeffs(ctx, mat);
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@ -1775,8 +1780,6 @@ static void rematrix_channels(MLPEncodeContext *ctx)
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unsigned int maxchan = ctx->num_channels;
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for (unsigned int mat = 0; mat < mp->count; mat++) {
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unsigned int msb_mask_bits = (ctx->avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 8 : 0) - mp->shift[mat];
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int32_t mask = MSB_MASK(msb_mask_bits);
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unsigned int outch = mp->outch[mat];
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sample_buffer = ctx->sample_buffer;
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@ -1787,7 +1790,7 @@ static void rematrix_channels(MLPEncodeContext *ctx)
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int32_t sample = *(sample_buffer + src_ch);
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accum += (int64_t) sample * mp->forco[mat][src_ch];
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}
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sample_buffer[outch] = (accum >> 14) & mask;
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sample_buffer[outch] = accum >> 14;
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sample_buffer += ctx->num_channels;
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}
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