diff options
Diffstat (limited to 'ffmpeg1/libavcodec/ac3enc_fixed.c')
| -rw-r--r-- | ffmpeg1/libavcodec/ac3enc_fixed.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/ac3enc_fixed.c b/ffmpeg1/libavcodec/ac3enc_fixed.c new file mode 100644 index 0000000..5d8dd5c --- /dev/null +++ b/ffmpeg1/libavcodec/ac3enc_fixed.c @@ -0,0 +1,169 @@ +/* + * The simplest AC-3 encoder + * Copyright (c) 2000 Fabrice Bellard + * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com> + * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * fixed-point AC-3 encoder. + */ + +#define CONFIG_FFT_FLOAT 0 +#undef CONFIG_AC3ENC_FLOAT +#include "internal.h" +#include "ac3enc.h" +#include "eac3enc.h" + +#define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED +#include "ac3enc_opts_template.c" + +static const AVClass ac3enc_class = { + .class_name = "Fixed-Point AC-3 Encoder", + .item_name = av_default_item_name, + .option = ac3_options, + .version = LIBAVUTIL_VERSION_INT, +}; + +#include "ac3enc_template.c" + + +/** + * Finalize MDCT and free allocated memory. + * + * @param s AC-3 encoder private context + */ +av_cold void AC3_NAME(mdct_end)(AC3EncodeContext *s) +{ + ff_mdct_end(&s->mdct); +} + + +/** + * Initialize MDCT tables. + * + * @param s AC-3 encoder private context + * @return 0 on success, negative error code on failure + */ +av_cold int AC3_NAME(mdct_init)(AC3EncodeContext *s) +{ + int ret = ff_mdct_init(&s->mdct, 9, 0, -1.0); + s->mdct_window = ff_ac3_window; + return ret; +} + + +/* + * Apply KBD window to input samples prior to MDCT. + */ +static void apply_window(void *dsp, int16_t *output, const int16_t *input, + const int16_t *window, unsigned int len) +{ + DSPContext *dsp0 = dsp; + dsp0->apply_window_int16(output, input, window, len); +} + + +/* + * Normalize the input samples to use the maximum available precision. + * This assumes signed 16-bit input samples. + */ +static int normalize_samples(AC3EncodeContext *s) +{ + int v = s->ac3dsp.ac3_max_msb_abs_int16(s->windowed_samples, AC3_WINDOW_SIZE); + v = 14 - av_log2(v); + if (v > 0) + s->ac3dsp.ac3_lshift_int16(s->windowed_samples, AC3_WINDOW_SIZE, v); + /* +6 to right-shift from 31-bit to 25-bit */ + return v + 6; +} + + +/* + * Scale MDCT coefficients to 25-bit signed fixed-point. + */ +static void scale_coefficients(AC3EncodeContext *s) +{ + int blk, ch; + + for (blk = 0; blk < s->num_blocks; blk++) { + AC3Block *block = &s->blocks[blk]; + for (ch = 1; ch <= s->channels; ch++) { + s->ac3dsp.ac3_rshift_int32(block->mdct_coef[ch], AC3_MAX_COEFS, + block->coeff_shift[ch]); + } + } +} + +static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4], + const int32_t *coef0, const int32_t *coef1, + int len) +{ + s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len); +} + +/* + * Clip MDCT coefficients to allowable range. + */ +static void clip_coefficients(DSPContext *dsp, int32_t *coef, unsigned int len) +{ + dsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len); +} + + +/* + * Calculate a single coupling coordinate. + */ +static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl) +{ + if (energy_cpl <= COEF_MAX) { + return 1048576; + } else { + uint64_t coord = energy_ch / (energy_cpl >> 24); + uint32_t coord32 = FFMIN(coord, 1073741824); + coord32 = ff_sqrt(coord32) << 9; + return FFMIN(coord32, COEF_MAX); + } +} + + +static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx) +{ + AC3EncodeContext *s = avctx->priv_data; + s->fixed_point = 1; + return ff_ac3_encode_init(avctx); +} + + +AVCodec ff_ac3_fixed_encoder = { + .name = "ac3_fixed", + .type = AVMEDIA_TYPE_AUDIO, + .id = AV_CODEC_ID_AC3, + .priv_data_size = sizeof(AC3EncodeContext), + .init = ac3_fixed_encode_init, + .encode2 = ff_ac3_fixed_encode_frame, + .close = ff_ac3_encode_close, + .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16P, + AV_SAMPLE_FMT_NONE }, + .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"), + .priv_class = &ac3enc_class, + .channel_layouts = ff_ac3_channel_layouts, + .defaults = ac3_defaults, +}; |