From 89df5e95bb7206fb090862f934333d555a7e2f42 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 30 Aug 2008 10:47:13 +0000 Subject: [PATCH] Replace obfuscated mdct in qmf_32_subbands() by ff_imdct_half(). Originally committed as revision 15049 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/dca.c | 65 +++++++++++++++++++++++++++--------------------- 1 file changed, 37 insertions(+), 28 deletions(-) diff --git a/libavcodec/dca.c b/libavcodec/dca.c index 071042fcd6..17e7366d46 100644 --- a/libavcodec/dca.c +++ b/libavcodec/dca.c @@ -157,7 +157,7 @@ typedef struct { /* Subband samples history (for ADPCM) */ float subband_samples_hist[DCA_PRIM_CHANNELS_MAX][DCA_SUBBANDS][4]; - float subband_fir_hist[DCA_PRIM_CHANNELS_MAX][512]; + DECLARE_ALIGNED_16(float, subband_fir_hist[DCA_PRIM_CHANNELS_MAX][512]); float subband_fir_noidea[DCA_PRIM_CHANNELS_MAX][32]; int hist_index[DCA_PRIM_CHANNELS_MAX]; @@ -177,6 +177,7 @@ typedef struct { int debug_flag; ///< used for suppressing repeated error messages output DSPContext dsp; + MDCTContext imdct; } DCAContext; static av_cold void dca_init_vlcs(void) @@ -656,15 +657,15 @@ static void qmf_32_subbands(DCAContext * s, int chans, float scale, float bias) { const float *prCoeff; - int i, j, k; - float praXin[33], *raXin = &praXin[1]; + int i, j; + DECLARE_ALIGNED_16(float, raXin[32]); int hist_index= s->hist_index[chans]; float *subband_fir_hist2 = s->subband_fir_noidea[chans]; - int chindex = 0, subindex; + int subindex; - praXin[0] = 0.0; + scale *= sqrt(1/8.0); /* Select filter */ if (!s->multirate_inter) /* Non-perfect reconstruction */ @@ -676,39 +677,39 @@ static void qmf_32_subbands(DCAContext * s, int chans, for (subindex = 0; subindex < 8; subindex++) { float *subband_fir_hist = s->subband_fir_hist[chans] + hist_index; /* Load in one sample from each subband and clear inactive subbands */ - for (i = 0; i < s->subband_activity[chans]; i++) - raXin[i] = samples_in[i][subindex]; + for (i = 0; i < s->subband_activity[chans]; i++){ + if((i-1)&2) raXin[i] = -samples_in[i][subindex]; + else raXin[i] = samples_in[i][subindex]; + } for (; i < 32; i++) raXin[i] = 0.0; - /* Multiply by cosine modulation coefficients and - * create temporary arrays SUM and DIFF */ - for (j = 0, k = 0; k < 16; k++) { - float t1 = 0.0; - float t2 = 0.0; - for (i = 0; i < 16; i++, j++){ - t1 += (raXin[2 * i] + raXin[2 * i + 1]) * cos_mod[j]; - t2 += (raXin[2 * i] + raXin[2 * i - 1]) * cos_mod[j + 256]; - } - subband_fir_hist[ k ] = cos_mod[k+512 ] * (t1 + t2); - subband_fir_hist[32-k-1] = cos_mod[k+512+16] * (t1 - t2); - } + ff_imdct_half(&s->imdct, subband_fir_hist, raXin); /* Multiply by filter coefficients */ - for (k = 31, i = 0; i < 32; i++, k--){ - float a= subband_fir_hist2[i]; - float b= 0; + for (i = 0; i < 16; i++){ + float a= subband_fir_hist2[i ]; + float b= subband_fir_hist2[i+16]; + float c= 0; + float d= 0; for (j = 0; j < 512-hist_index; j += 64){ - a += prCoeff[i+j ]*( subband_fir_hist[i+j] - subband_fir_hist[j+k]); - b += prCoeff[i+j+32]*(-subband_fir_hist[i+j] - subband_fir_hist[j+k]); + a += prCoeff[i+j ]*(-subband_fir_hist[15-i+j]); + b += prCoeff[i+j+16]*( subband_fir_hist[ i+j]); + c += prCoeff[i+j+32]*( subband_fir_hist[16+i+j]); + d += prCoeff[i+j+48]*( subband_fir_hist[31-i+j]); } for ( ; j < 512; j += 64){ - a += prCoeff[i+j ]*( subband_fir_hist[i+j-512] - subband_fir_hist[j+k-512]); - b += prCoeff[i+j+32]*(-subband_fir_hist[i+j-512] - subband_fir_hist[j+k-512]); + a += prCoeff[i+j ]*(-subband_fir_hist[15-i+j-512]); + b += prCoeff[i+j+16]*( subband_fir_hist[ i+j-512]); + c += prCoeff[i+j+32]*( subband_fir_hist[16+i+j-512]); + d += prCoeff[i+j+48]*( subband_fir_hist[31-i+j-512]); } - samples_out[chindex++] = a * scale + bias; - subband_fir_hist2[i] = b; + samples_out[i ] = a * scale + bias; + samples_out[i+16] = b * scale + bias; + subband_fir_hist2[i ] = c; + subband_fir_hist2[i+16] = d; } + samples_out+= 32; hist_index = (hist_index-32)&511; } @@ -1237,6 +1238,7 @@ static av_cold int dca_decode_init(AVCodecContext * avctx) pre_calc_cosmod(s); dsputil_init(&s->dsp, avctx); + ff_mdct_init(&s->imdct, 6, 1); /* allow downmixing to stereo */ if (avctx->channels > 0 && avctx->request_channels < avctx->channels && @@ -1249,6 +1251,12 @@ static av_cold int dca_decode_init(AVCodecContext * avctx) return 0; } +static av_cold int dca_decode_end(AVCodecContext * avctx) +{ + DCAContext *s = avctx->priv_data; + ff_mdct_end(&s->imdct); + return 0; +} AVCodec dca_decoder = { .name = "dca", @@ -1257,5 +1265,6 @@ AVCodec dca_decoder = { .priv_data_size = sizeof(DCAContext), .init = dca_decode_init, .decode = dca_decode_frame, + .close = dca_decode_end, .long_name = NULL_IF_CONFIG_SMALL("DCA (DTS Coherent Acoustics)"), };