From 41277578b93941bbf98b7820c5dbb9bdad49cffe Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Sat, 14 Jul 2007 15:51:00 +0000 Subject: [PATCH] AC-3 decoder, soc revision 34, Jul 18 14:27:54 2006 UTC by cloud9 working decoder imdct for block switching is to be implemented various other things to do Originally committed as revision 9656 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/ac3dec.c | 71 ++++++++++----------------------------------- 1 file changed, 15 insertions(+), 56 deletions(-) diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index 216514dcf0..53b0202d09 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -38,6 +38,7 @@ #define BLOCK_SIZE 256 #define AUDIO_BLOCKS 6 + /* Synchronization information. */ typedef struct { uint16_t sync_word; //synchronization word = always 0x0b77 @@ -891,6 +892,7 @@ static int get_transform_coeffs_ch(uint8_t *exps, uint8_t *bap, float chcoeff, } else { TRANSFORM_COEFF(coeffs[i], dither_int16(state), exps[i], factors); + coeffs[i] *= LEVEL_PLUS_3DB; continue; } @@ -1482,39 +1484,13 @@ static void dump_floats(const char *name, int prec, const float *tab, int n) av_log(NULL, AV_LOG_INFO, "\n"); } -/*static void window_and_de_interleave(float *output) -{ - int n2, n4, n8; - int k; - - n2 = 512 >> 1; - n4 = 512 >> 2; - n8 = 512 >> 3; - - for (k = 0; k < n8; k++) { - output[2 * k] *= window[2 * k]; - output[n2 - 2 * k - 1] *= window[n2 - 2 * k - 1]; - - output[2 * k + 1] *= window[2 * k + 1]; - output[n2 - 2 * k - 2] *= window[n2 - 2 * k - 2]; - - output[n2 + 2 * k] *= window[n2 - 2 * k - 1]; - output[n - 2 * k - 1] *= window[n - 2 * k - 1]; - - output[n2 + 2 * k + 1] *= window[n2 - 2 * k - 2]; - output[n - 2 * k - 2] *= window[n - 2 * k - 2]; - output[3 * n4 + 2 * k + 1] *= window[n4 - 2 * k - 2]; - } -}*/ - static inline void overlap_and_add(float *tmp_output, float *delay, float *output) { int n; - for (n = 0; n < BLOCK_SIZE; n++) { - output[n] = 2 * (tmp_output[n] * window[n] + delay[n] * window[255 - n]); - delay[n] = tmp_output[BLOCK_SIZE + n]; - } + for (n = 0; n < BLOCK_SIZE; n++) + output[n] = (tmp_output[n] * window[n] + delay[n] * window[255 - n]); + memcpy(delay, tmp_output + BLOCK_SIZE, BLOCK_SIZE * sizeof (float)); } @@ -1526,14 +1502,12 @@ static inline void do_imdct(AC3DecodeContext *ctx) if (ctx->output & AC3_OUTPUT_LFEON) { av_log(NULL, AV_LOG_INFO, "imdct lfe\n"); ff_imdct_calc(&ctx->imdct_ctx_512, ab->tmp_output, ab->transform_coeffs[0], ab->tmp_imdct); - //window_and_de_interleave(ab->tmp_output); overlap_and_add(ab->tmp_output, ab->delay[0], ab->output[0]); } - for (i = 0; i < ctx->bsi.nfchans; i++) { + for (i = 0; i < ctx->bsi.nfchans + 1; i++) { if (!(((ab->blksw) >> i) & 1)) { - av_log(NULL, AV_LOG_INFO, "imdct channel %d - block switching not enabled\n", i); + //av_log(NULL, AV_LOG_INFO, "imdct channel %d - block switching not enabled\n", i); ff_imdct_calc(&ctx->imdct_ctx_512, ab->tmp_output, ab->transform_coeffs[i + 1], ab->tmp_imdct); - //window_and_de_interleave(ab->tmp_output); overlap_and_add(ab->tmp_output, ab->delay[i + 1], ab->output[i + 1]); } else { av_log(NULL, AV_LOG_INFO, "imdct channel %d skipping - block switching enabled\n", i); @@ -1541,8 +1515,6 @@ static inline void do_imdct(AC3DecodeContext *ctx) } } - - static int ac3_parse_audio_block(AC3DecodeContext * ctx, int index) { ac3_audio_block *ab = &ctx->audio_block; @@ -1559,7 +1531,7 @@ static int ac3_parse_audio_block(AC3DecodeContext * ctx, int index) *flags = 0; ab->blksw = 0; for (i = 0; i < 5; i++) - ab->chcoeffs[i] = 1.0; + ab->chcoeffs[i] = 2.0; for (i = 0; i < nfchans; i++) /*block switch flag */ ab->blksw |= get_bits1(gb) << i; ab->dithflag = 0; @@ -1825,30 +1797,15 @@ static int ac3_parse_audio_block(AC3DecodeContext * ctx, int index) return 0; } -/* from FreeSWITCH Modular Media Switching Library */ -#define NORMFACT (float)0x8000 -#define MAXSAMPLE (float)0x7fff - - static inline int16_t convert(float f) { - /*short s; - f = f * NORMFACT; - if (f >= 0) - s = (short)(f + 0.5); - else - s = (short)(f - 0.5); - if ((float)s > MAXSAMPLE) - s = (float)MAXSAMPLE; - if (s < (short) -MAXSAMPLE) - s = (short) -MAXSAMPLE; - - return s;*/ int a; a = lrintf(f * 32767.0); return ((int16_t)a); } +static int frame_count = 0; + static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size) { AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data; @@ -1857,6 +1814,8 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, int16_t *out_samples = (int16_t *)data; int i, j, k, value; + av_log(NULL, AV_LOG_INFO, "decoding frame %d buf_size = %d\n", frame_count++, buf_size); + //Synchronize the frame. frame_start = ac3_synchronize(buf, buf_size); if (frame_start == -1) { @@ -1919,10 +1878,10 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, return ctx->sync_info.framesize; } j = ((ctx->output & AC3_OUTPUT_LFEON) ? 0 : 1); - for (;j < avctx->channels; j++) { - for(k = 0; k < BLOCK_SIZE; k++) { + for (k = 0; k < BLOCK_SIZE; k++) { + j = ((ctx->output & AC3_OUTPUT_LFEON) ? 0 : 1); + for (;j < avctx->channels + 1; j++) { value = convert(ab->output[j][k]); - av_log(NULL, AV_LOG_INFO, "%d\t", value); *(out_samples++) = value; } }