diff options
| -rw-r--r-- | libavcodec/Makefile | 1 | ||||
| -rw-r--r-- | libavcodec/alacenc.c | 110 | ||||
| -rw-r--r-- | libavcodec/allcodecs.c | 2 |
3 files changed, 112 insertions, 1 deletions
diff --git a/libavcodec/Makefile b/libavcodec/Makefile index b6b39bf410..88fc78ba6c 100644 --- a/libavcodec/Makefile +++ b/libavcodec/Makefile @@ -29,6 +29,7 @@ OBJS-$(CONFIG_AASC_DECODER) += aasc.o OBJS-$(CONFIG_AC3_DECODER) += ac3dec.o ac3tab.o ac3dec_data.o ac3.o mdct.o fft.o OBJS-$(CONFIG_AC3_ENCODER) += ac3enc.o ac3tab.o ac3.o OBJS-$(CONFIG_ALAC_DECODER) += alac.o +OBJS-$(CONFIG_ALAC_ENCODER) += alacenc.o lpc.o OBJS-$(CONFIG_AMV_DECODER) += sp5xdec.o mjpegdec.o mjpeg.o OBJS-$(CONFIG_APE_DECODER) += apedec.o OBJS-$(CONFIG_ASV1_DECODER) += asv1.o mpeg12data.o diff --git a/libavcodec/alacenc.c b/libavcodec/alacenc.c index d6332bff28..a1fb66f9e2 100644 --- a/libavcodec/alacenc.c +++ b/libavcodec/alacenc.c @@ -217,6 +217,114 @@ static void alac_stereo_decorrelation(AlacEncodeContext *s) } } +static void alac_linear_predictor(AlacEncodeContext *s, int ch) +{ + int i; + LPCContext lpc = s->lpc[ch]; + + if(lpc.lpc_order == 31) { + s->predictor_buf[0] = s->sample_buf[ch][0]; + + for(i=1; i<s->avctx->frame_size; i++) + s->predictor_buf[i] = s->sample_buf[ch][i] - s->sample_buf[ch][i-1]; + + return; + } + + // generalised linear predictor + + if(lpc.lpc_order > 0) { + int32_t *samples = s->sample_buf[ch]; + int32_t *residual = s->predictor_buf; + + // generate warm-up samples + residual[0] = samples[0]; + for(i=1;i<=lpc.lpc_order;i++) + residual[i] = samples[i] - samples[i-1]; + + // perform lpc on remaining samples + for(i = lpc.lpc_order + 1; i < s->avctx->frame_size; i++) { + int sum = 1 << (lpc.lpc_quant - 1), res_val, j; + + for (j = 0; j < lpc.lpc_order; j++) { + sum += (samples[lpc.lpc_order-j] - samples[0]) * + lpc.lpc_coeff[j]; + } + + sum >>= lpc.lpc_quant; + sum += samples[0]; + residual[i] = samples[lpc.lpc_order+1] - sum; + res_val = residual[i]; + + if(res_val) { + int index = lpc.lpc_order - 1; + int neg = (res_val < 0); + + while(index >= 0 && (neg ? (res_val < 0):(res_val > 0))) { + int val = samples[0] - samples[lpc.lpc_order - index]; + int sign = (val ? FFSIGN(val) : 0); + + if(neg) + sign*=-1; + + lpc.lpc_coeff[index] -= sign; + val *= sign; + res_val -= ((val >> lpc.lpc_quant) * + (lpc.lpc_order - index)); + index--; + } + } + samples++; + } + } +} + +static void alac_entropy_coder(AlacEncodeContext *s) +{ + unsigned int history = s->rc.initial_history; + int sign_modifier = 0, i, k; + int32_t *samples = s->predictor_buf; + + for(i=0;i < s->avctx->frame_size;) { + int x; + + k = av_log2((history >> 9) + 3); + + x = -2*(*samples)-1; + x ^= (x>>31); + + samples++; + i++; + + encode_scalar(s, x - sign_modifier, k, s->write_sample_size); + + history += x * s->rc.history_mult + - ((history * s->rc.history_mult) >> 9); + + sign_modifier = 0; + if(x > 0xFFFF) + history = 0xFFFF; + + if((history < 128) && (i < s->avctx->frame_size)) { + unsigned int block_size = 0; + + k = 7 - av_log2(history) + ((history + 16) >> 6); + + while((*samples == 0) && (i < s->avctx->frame_size)) { + samples++; + i++; + block_size++; + } + encode_scalar(s, block_size, k, 16); + + sign_modifier = (block_size <= 0xFFFF); + + history = 0; + } + + } +} + static void write_compressed_frame(AlacEncodeContext *s) { int i, j; @@ -295,6 +403,7 @@ static av_cold int alac_encode_init(AVCodecContext *avctx) AV_WB8(alac_extradata+20, s->rc.k_modifier); } + s->min_prediction_order = DEFAULT_MIN_PRED_ORDER; if(avctx->min_prediction_order >= 0) { if(avctx->min_prediction_order < MIN_LPC_ORDER || avctx->min_prediction_order > MAX_LPC_ORDER) { @@ -305,6 +414,7 @@ static av_cold int alac_encode_init(AVCodecContext *avctx) s->min_prediction_order = avctx->min_prediction_order; } + s->max_prediction_order = DEFAULT_MAX_PRED_ORDER; if(avctx->max_prediction_order >= 0) { if(avctx->max_prediction_order < MIN_LPC_ORDER || avctx->max_prediction_order > MAX_LPC_ORDER) { diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c index b3da4da544..1f202267ab 100644 --- a/libavcodec/allcodecs.c +++ b/libavcodec/allcodecs.c @@ -182,7 +182,7 @@ void avcodec_register_all(void) /* audio codecs */ REGISTER_ENCDEC (AC3, ac3); - REGISTER_DECODER (ALAC, alac); + REGISTER_ENCDEC (ALAC, alac); REGISTER_DECODER (APE, ape); REGISTER_DECODER (ATRAC3, atrac3); REGISTER_DECODER (COOK, cook); |