| /* |
| * 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 |
| * floating-point AC-3 encoder. |
| */ |
| |
| #define CONFIG_AC3ENC_FLOAT 1 |
| #include "ac3enc.h" |
| #include "eac3enc.h" |
| #include "kbdwin.h" |
| |
| |
| #if CONFIG_AC3_ENCODER |
| #define AC3ENC_TYPE AC3ENC_TYPE_AC3 |
| #include "ac3enc_opts_template.c" |
| static AVClass ac3enc_class = { "AC-3 Encoder", av_default_item_name, |
| ac3_options, LIBAVUTIL_VERSION_INT }; |
| #endif |
| |
| #include "ac3enc_template.c" |
| |
| |
| /** |
| * Finalize MDCT and free allocated memory. |
| */ |
| av_cold void ff_ac3_float_mdct_end(AC3MDCTContext *mdct) |
| { |
| ff_mdct_end(&mdct->fft); |
| av_freep(&mdct->window); |
| } |
| |
| |
| /** |
| * Initialize MDCT tables. |
| * @param nbits log2(MDCT size) |
| */ |
| av_cold int ff_ac3_float_mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct, |
| int nbits) |
| { |
| float *window; |
| int i, n, n2; |
| |
| n = 1 << nbits; |
| n2 = n >> 1; |
| |
| window = av_malloc(n * sizeof(*window)); |
| if (!window) { |
| av_log(avctx, AV_LOG_ERROR, "Cannot allocate memory.\n"); |
| return AVERROR(ENOMEM); |
| } |
| ff_kbd_window_init(window, 5.0, n2); |
| for (i = 0; i < n2; i++) |
| window[n-1-i] = window[i]; |
| mdct->window = window; |
| |
| return ff_mdct_init(&mdct->fft, nbits, 0, -2.0 / n); |
| } |
| |
| |
| /** |
| * Apply KBD window to input samples prior to MDCT. |
| */ |
| void ff_ac3_float_apply_window(DSPContext *dsp, float *output, |
| const float *input, const float *window, |
| unsigned int len) |
| { |
| dsp->vector_fmul(output, input, window, len); |
| } |
| |
| |
| /** |
| * Scale MDCT coefficients from float to 24-bit fixed-point. |
| */ |
| void ff_ac3_float_scale_coefficients(AC3EncodeContext *s) |
| { |
| int chan_size = AC3_MAX_COEFS * AC3_MAX_BLOCKS; |
| s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + chan_size, |
| s->mdct_coef_buffer + chan_size, |
| chan_size * s->channels); |
| } |
| |
| |
| #if CONFIG_AC3_ENCODER |
| AVCodec ff_ac3_float_encoder = { |
| "ac3_float", |
| AVMEDIA_TYPE_AUDIO, |
| CODEC_ID_AC3, |
| sizeof(AC3EncodeContext), |
| ff_ac3_encode_init, |
| ff_ac3_encode_frame, |
| ff_ac3_encode_close, |
| NULL, |
| .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,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, |
| }; |
| #endif |