/* * The simplest AC-3 encoder * Copyright (c) 2000 Fabrice Bellard * Copyright (c) 2006-2010 Justin Ruggles * Copyright (c) 2006-2010 Prakash Punnoor * * 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 * floating-point AC-3 encoder. */ #define AC3ENC_FLOAT 1 #include "audiodsp.h" #include "ac3enc.h" #include "codec_internal.h" #include "eac3enc.h" #include "kbdwin.h" /* * Scale MDCT coefficients from float to 24-bit fixed-point. */ static void scale_coefficients(AC3EncodeContext *s) { int chan_size = AC3_MAX_COEFS * s->num_blocks; int cpl = s->cpl_on; s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl), s->mdct_coef_buffer + (chan_size * !cpl), chan_size * (s->channels + cpl)); } /* * Clip MDCT coefficients to allowable range. */ static void clip_coefficients(AudioDSPContext *adsp, float *coef, unsigned int len) { adsp->vector_clipf(coef, coef, len, COEF_MIN, COEF_MAX); } /* * Calculate a single coupling coordinate. */ static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl) { float coord = 0.125; if (energy_cpl > 0) coord *= sqrtf(energy_ch / energy_cpl); return FFMIN(coord, COEF_MAX); } static void sum_square_butterfly(AC3EncodeContext *s, float sum[4], const float *coef0, const float *coef1, int len) { s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len); } #include "ac3enc_template.c" /** * Finalize MDCT and free allocated memory. * * @param s AC-3 encoder private context */ static av_cold void ac3_float_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 */ static av_cold int ac3_float_mdct_init(AC3EncodeContext *s) { float *window = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*window)); if (!window) { av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n"); return AVERROR(ENOMEM); } ff_kbd_window_init(window, 5.0, AC3_BLOCK_SIZE); s->mdct_window = window; return ff_mdct_init(&s->mdct, 9, 0, -2.0 / AC3_WINDOW_SIZE); } av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx) { AC3EncodeContext *s = avctx->priv_data; s->mdct_end = ac3_float_mdct_end; s->mdct_init = ac3_float_mdct_init; s->allocate_sample_buffers = allocate_sample_buffers; s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT); if (!s->fdsp) return AVERROR(ENOMEM); return ff_ac3_encode_init(avctx); } FF_DISABLE_DEPRECATION_WARNINGS const FFCodec ff_ac3_encoder = { .p.name = "ac3", CODEC_LONG_NAME("ATSC A/52A (AC-3)"), .p.type = AVMEDIA_TYPE_AUDIO, .p.id = AV_CODEC_ID_AC3, .p.capabilities = AV_CODEC_CAP_DR1, .priv_data_size = sizeof(AC3EncodeContext), .init = ff_ac3_float_encode_init, FF_CODEC_ENCODE_CB(ff_ac3_float_encode_frame), .close = ff_ac3_encode_close, .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE }, .p.priv_class = &ff_ac3enc_class, .p.supported_samplerates = ff_ac3_sample_rate_tab, #if FF_API_OLD_CHANNEL_LAYOUT .p.channel_layouts = ff_ac3_channel_layouts, #endif .p.ch_layouts = ff_ac3_ch_layouts, .defaults = ff_ac3_enc_defaults, .caps_internal = FF_CODEC_CAP_INIT_CLEANUP, }; FF_ENABLE_DEPRECATION_WARNINGS