From 10634c037aebbcaa1e6e2ef9c25bb822a741a100 Mon Sep 17 00:00:00 2001 From: Benjamin Larsson Date: Thu, 17 Sep 2009 18:52:11 +0000 Subject: [PATCH] Only use one mdct window size in atrac1. Originally committed as revision 19900 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/atrac1.c | 72 ++++++++++++++------------------------------- 1 file changed, 22 insertions(+), 50 deletions(-) diff --git a/libavcodec/atrac1.c b/libavcodec/atrac1.c index 5a68fbfc72..42c4801fb6 100644 --- a/libavcodec/atrac1.c +++ b/libavcodec/atrac1.c @@ -73,7 +73,8 @@ typedef struct { typedef struct { AT1SUCtx SUs[AT1_MAX_CHANNELS]; ///< channel sound unit DECLARE_ALIGNED_16(float,spec[AT1_SU_SAMPLES]); ///< the mdct spectrum buffer - DECLARE_ALIGNED_16(float,short_buf[64]); ///< buffer for the short mode + DECLARE_ALIGNED_16(float,short_buf[512]); ///< buffer for the short mode + DECLARE_ALIGNED_16(float, low[256]); DECLARE_ALIGNED_16(float, mid[256]); DECLARE_ALIGNED_16(float,high[512]); @@ -84,10 +85,7 @@ typedef struct { DSPContext dsp; } AT1Ctx; -static float *short_window; -static float *mid_window; -DECLARE_ALIGNED_16(static float, long_window[256]); -static float *window_per_band[3]; +DECLARE_ALIGNED_16(static float, short_window[32]); /** size of the transform in samples in the long mode for each QMF band */ static const uint16_t samples_per_band[3] = {128, 128, 256}; @@ -137,28 +135,37 @@ static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q) if (num_blocks == 1) { at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos], nbits, band_num); pos += block_size; // move to the next mdct block in the spectrum + + /* overlap and window long blocks */ + q->dsp.vector_fmul_window(q->bands[band_num], &su->spectrum[1][ref_pos+band_samples-16], + &su->spectrum[0][ref_pos], short_window, 0, 16); + memcpy(q->bands[band_num]+32, &su->spectrum[0][ref_pos+16], 240 * sizeof(float)); + } else { /* calc start position for the 1st short block: 96(128) or 112(256) */ + int short_pos = 32; + float *prev_buf; start_pos = (band_samples * (num_blocks - 1)) >> (log2_block_count + 1); memset(&su->spectrum[0][ref_pos], 0, sizeof(float) * (band_samples * 2)); + prev_buf = &su->spectrum[1][ref_pos+band_samples-16]; for (; num_blocks!=0 ; num_blocks--) { /* use hardcoded nbits for the short mode */ - at1_imdct(q, &q->spec[pos], q->short_buf, 5, band_num); + at1_imdct(q, &q->spec[pos], &q->short_buf[short_pos], 5, band_num); /* overlap and window between short blocks */ q->dsp.vector_fmul_window(&su->spectrum[0][ref_pos+start_pos], - &su->spectrum[0][ref_pos+start_pos], - q->short_buf,short_window, 0, 16); + &q->short_buf[short_pos-16], + &q->short_buf[short_pos],short_window, 0, 16); + + prev_buf = &q->short_buf[short_pos+16]; + start_pos += 32; // use hardcoded block_size pos += 32; + short_pos +=32; } + memcpy(q->bands[band_num], &su->spectrum[0][ref_pos], band_samples*sizeof(float)); } - - /* overlap and window with the previous frame and output the result */ - q->dsp.vector_fmul_window(q->bands[band_num], &su->spectrum[1][ref_pos+band_samples/2], - &su->spectrum[0][ref_pos], window_per_band[band_num], 0, band_samples/2); - ref_pos += band_samples; } @@ -331,42 +338,6 @@ static int atrac1_decode_frame(AVCodecContext *avctx, void *data, } -static av_cold void init_mdct_windows(void) -{ - int i; - - /** The mid and long windows uses the same sine window splitted - * in the middle and wrapped into zero/one regions as follows: - * - * region of "ones" - * ------------- - * / - * / 1st half - * / of the sine - * / window - * ---------/ - * zero region - * - * The mid and short windows are subsets of the long window. - */ - - /* Build "zero" region */ - memset(long_window, 0, sizeof(long_window)); - /* Build sine window region */ - short_window = &long_window[112]; - ff_sine_window_init(short_window,32); - /* Build "ones" region */ - for (i = 0; i < 112; i++) - long_window[144 + i] = 1.0f; - /* Save the mid window subset start */ - mid_window = &long_window[64]; - - /* Prepare the window table */ - window_per_band[0] = mid_window; - window_per_band[1] = mid_window; - window_per_band[2] = long_window; -} - static av_cold int atrac1_decode_init(AVCodecContext *avctx) { AT1Ctx *q = avctx->priv_data; @@ -379,7 +350,8 @@ static av_cold int atrac1_decode_init(AVCodecContext *avctx) ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1<<15)); ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1<<15)); ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1<<15)); - init_mdct_windows(); + + ff_sine_window_init(short_window, 32); atrac_generate_tables();