atrac3: Generalize gain compensation code
Move it to the ATRAC common code, so it can be reused in the umpcoming ATRAC3+ decoder. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Maxim Poliakovski
Michael Niedermayer
parent
4fa2484067
commit
d49f3fa579
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@ -63,6 +63,67 @@ av_cold void ff_atrac_generate_tables(void)
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}
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}
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av_cold void ff_atrac_init_gain_compensation(AtracGCContext *gctx, int id2exp_offset,
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int loc_scale)
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{
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int i;
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gctx->loc_scale = loc_scale;
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gctx->loc_size = 1 << loc_scale;
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gctx->id2exp_offset = id2exp_offset;
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/* Generate gain level table. */
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for (i = 0; i < 16; i++)
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gctx->gain_tab1[i] = powf(2.0, id2exp_offset - i);
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/* Generate gain interpolation table. */
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for (i = -15; i < 16; i++)
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gctx->gain_tab2[i + 15] = powf(2.0, -1.0f / gctx->loc_size * i);
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}
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void ff_atrac_gain_compensation(AtracGCContext *gctx, float *in, float *prev,
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AtracGainInfo *gc_now, AtracGainInfo *gc_next,
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int num_samples, float *out)
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{
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float lev, gc_scale, gain_inc;
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int i, pos, lastpos;
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gc_scale = gc_next->num_points ? gctx->gain_tab1[gc_next->levcode[0]] : 1.0f;
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if (!gc_now->num_points) {
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for (pos = 0; pos < num_samples; pos++)
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out[pos] = in[pos] * gc_scale + prev[pos];
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} else {
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pos = 0;
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for (i = 0; i < gc_now->num_points; i++) {
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lastpos = gc_now->loccode[i] << gctx->loc_scale;
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lev = gctx->gain_tab1[gc_now->levcode[i]];
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gain_inc = gctx->gain_tab2[(i + 1 < gc_now->num_points
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? gc_now->levcode[i + 1]
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: gctx->id2exp_offset)
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- gc_now->levcode[i] + 15];
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/* apply constant gain level and overlap */
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for (; pos < lastpos; pos++)
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out[pos] = (in[pos] * gc_scale + prev[pos]) * lev;
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/* interpolate between two different gain levels */
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for (; pos < lastpos + gctx->loc_size; pos++) {
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out[pos] = (in[pos] * gc_scale + prev[pos]) * lev;
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lev *= gain_inc;
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}
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}
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for (; pos < num_samples; pos++)
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out[pos] = in[pos] * gc_scale + prev[pos];
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}
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/* copy the overlapping part into the delay buffer */
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memcpy(prev, &in[num_samples], num_samples * sizeof(float));
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}
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void ff_atrac_iqmf(float *inlo, float *inhi, unsigned int nIn, float *pOut,
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float *delayBuf, float *temp)
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{
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@ -29,6 +29,26 @@
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#ifndef AVCODEC_ATRAC_H
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#define AVCODEC_ATRAC_H
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/**
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* Gain control parameters for one subband.
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*/
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typedef struct AtracGainInfo {
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int num_points; ///< number of gain control points
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int levcode[7]; ///< level at corresponding control point
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int loccode[7]; ///< location of gain control points
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} AtracGainInfo;
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/**
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* Gain compensation context structure.
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*/
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typedef struct AtracGCContext {
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float gain_tab1[16]; ///< gain compensation level table
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float gain_tab2[31]; ///< gain compensation interpolation table
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int id2exp_offset; ///< offset for converting level index into level exponent
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int loc_scale; ///< scale of location code = 2^loc_scale samples
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int loc_size; ///< size of location code in samples
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} AtracGCContext;
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extern float ff_atrac_sf_table[64];
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/**
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@ -36,6 +56,31 @@ extern float ff_atrac_sf_table[64];
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*/
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void ff_atrac_generate_tables(void);
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/**
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* Initialize gain compensation context.
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*
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* @param gctx pointer to gain compensation context to initialize
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* @param id2exp_offset offset for converting level index into level exponent
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* @param loc_scale location size factor
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*/
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void ff_atrac_init_gain_compensation(AtracGCContext *gctx, int id2exp_offset,
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int loc_scale);
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/**
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* Apply gain compensation and perform the MDCT overlapping part.
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*
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* @param gctx pointer to gain compensation context
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* @param in input buffer
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* @param prev previous buffer to perform overlap against
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* @param gc_now gain control information for current frame
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* @param gc_next gain control information for next frame
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* @param num_samples number of samples to process
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* @param out output data goes here
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*/
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void ff_atrac_gain_compensation(AtracGCContext *gctx, float *in, float *prev,
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AtracGainInfo *gc_now, AtracGainInfo *gc_next,
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int num_samples, float *out);
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/**
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* Quadrature mirror synthesis filter.
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*
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@ -55,12 +55,6 @@
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#define SAMPLES_PER_FRAME 1024
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#define MDCT_SIZE 512
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typedef struct AtracGainInfo {
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int num_points;
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int lev_code[8];
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int loc_code[8];
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} AtracGainInfo;
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typedef struct GainBlock {
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AtracGainInfo g_block[4];
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} GainBlock;
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@ -112,7 +106,8 @@ typedef struct ATRAC3Context {
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int scrambled_stream;
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//@}
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FFTContext mdct_ctx;
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AtracGCContext gainc_ctx;
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FFTContext mdct_ctx;
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FmtConvertContext fmt_conv;
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AVFloatDSPContext fdsp;
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} ATRAC3Context;
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@ -443,63 +438,6 @@ static int decode_gain_control(GetBitContext *gb, GainBlock *block,
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return 0;
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}
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/**
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* Apply gain parameters and perform the MDCT overlapping part
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*
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* @param input input buffer
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* @param prev previous buffer to perform overlap against
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* @param output output buffer
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* @param gain1 current band gain info
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* @param gain2 next band gain info
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*/
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static void gain_compensate_and_overlap(float *input, float *prev,
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float *output, AtracGainInfo *gain1,
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AtracGainInfo *gain2)
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{
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float g1, g2, gain_inc;
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int i, j, num_data, start_loc, end_loc;
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if (gain2->num_points == 0)
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g1 = 1.0;
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else
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g1 = gain_tab1[gain2->lev_code[0]];
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if (gain1->num_points == 0) {
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for (i = 0; i < 256; i++)
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output[i] = input[i] * g1 + prev[i];
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} else {
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num_data = gain1->num_points;
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gain1->loc_code[num_data] = 32;
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gain1->lev_code[num_data] = 4;
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for (i = 0, j = 0; i < num_data; i++) {
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start_loc = gain1->loc_code[i] * 8;
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end_loc = start_loc + 8;
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g2 = gain_tab1[gain1->lev_code[i]];
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gain_inc = gain_tab2[gain1->lev_code[i + 1] -
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gain1->lev_code[i ] + 15];
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/* interpolate */
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for (; j < start_loc; j++)
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output[j] = (input[j] * g1 + prev[j]) * g2;
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/* interpolation is done over eight samples */
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for (; j < end_loc; j++) {
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output[j] = (input[j] * g1 + prev[j]) * g2;
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g2 *= gain_inc;
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}
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}
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for (; j < 256; j++)
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output[j] = input[j] * g1 + prev[j];
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}
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/* Delay for the overlapping part. */
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memcpy(prev, &input[256], 256 * sizeof(*prev));
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}
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/**
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* Combine the tonal band spectrum and regular band spectrum
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*
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@ -690,11 +628,10 @@ static int decode_channel_sound_unit(ATRAC3Context *q, GetBitContext *gb,
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memset(snd->imdct_buf, 0, 512 * sizeof(*snd->imdct_buf));
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/* gain compensation and overlapping */
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gain_compensate_and_overlap(snd->imdct_buf,
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&snd->prev_frame[band * 256],
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&output[band * 256],
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&gain1->g_block[band],
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&gain2->g_block[band]);
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ff_atrac_gain_compensation(&q->gainc_ctx, snd->imdct_buf,
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&snd->prev_frame[band * 256],
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&gain1->g_block[band], &gain2->g_block[band],
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256, &output[band * 256]);
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}
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/* Swap the gain control buffers for the next frame. */
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@ -987,6 +924,7 @@ static av_cold int atrac3_decode_init(AVCodecContext *avctx)
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q->matrix_coeff_index_next[i] = 3;
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}
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ff_atrac_init_gain_compensation(&q->gainc_ctx, 4, 3);
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avpriv_float_dsp_init(&q->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
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ff_fmt_convert_init(&q->fmt_conv, avctx);
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