From 4e09232070475850ebb5e3e4a9b032d6198a33f0 Mon Sep 17 00:00:00 2001 From: Justin Ruggles <justin.ruggles@gmail.com> Date: Sat, 4 Aug 2007 20:59:22 +0000 Subject: use dsputil for float to signed 16-bit sample conversion Originally committed as revision 9914 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/ac3dec.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index a85c135afc..2c615d97b5 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -150,8 +150,11 @@ typedef struct { MDCTContext imdct_512; //for 512 sample imdct transform MDCTContext imdct_256; //for 256 sample imdct transform DSPContext dsp; //for optimization + float add_bias; ///< offset for float_to_int16 conversion + float mul_bias; ///< scaling for float_to_int16 conversion DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); //output after imdct transform and windowing + DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); //delay - added to the next block DECLARE_ALIGNED_16(float, tmp_imdct[256]); //temporary storage for imdct transform DECLARE_ALIGNED_16(float, tmp_output[512]); //temporary storage for output before windowing @@ -262,6 +265,14 @@ static int ac3_decode_init(AVCodecContext *avctx) dsputil_init(&ctx->dsp, avctx); av_init_random(0, &ctx->dith_state); + if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) { + ctx->add_bias = 385.0f; + ctx->mul_bias = 1.0f; + } else { + ctx->add_bias = 0.0f; + ctx->mul_bias = 32767.0f; + } + return 0; } /*********** END INIT FUNCTIONS ***********/ @@ -651,7 +662,7 @@ static inline void do_imdct(AC3DecodeContext *ctx) ctx->tmp_imdct); } ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output, - ctx->window, ctx->delay[ch-1], 384, 256, 1); + ctx->window, ctx->delay[ch-1], ctx->add_bias, 256, 1); ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256, ctx->window, 256); } @@ -921,7 +932,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk) /* apply scaling to coefficients (headroom, dynrng) */ for(ch=1; ch<=ctx->nchans; ch++) { - float gain = 2.0f; + float gain = 2.0f * ctx->mul_bias; if(ctx->acmod == AC3_ACMOD_DUALMONO && ch == 2) { gain *= ctx->dynrng2; } else { @@ -934,17 +945,12 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk) do_imdct(ctx); - return 0; -} + /* convert float to 16-bit integer */ + for(ch=0; ch<ctx->out_channels; ch++) { + ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256); + } -static inline int16_t convert(int32_t i) -{ - if (i > 0x43c07fff) - return 32767; - else if (i <= 0x43bf8000) - return -32768; - else - return (i - 0x43c00000); + return 0; } /* Decode ac3 frame. @@ -960,10 +966,6 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data; int16_t *out_samples = (int16_t *)data; int i, blk, ch; - int32_t *int_ptr[6]; - - for (ch = 0; ch < 6; ch++) - int_ptr[ch] = (int32_t *)(&ctx->output[ch]); //Initialize the GetBitContext with the start of valid AC3 Frame. init_get_bits(&ctx->gb, buf, buf_size * 8); @@ -999,7 +1001,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, } for (i = 0; i < 256; i++) for (ch = 0; ch < ctx->out_channels; ch++) - *(out_samples++) = convert(int_ptr[ch][i]); + *(out_samples++) = ctx->int_output[ch][i]; } *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t); return ctx->frame_size; -- cgit v1.2.3