mirror of https://github.com/FFmpeg/FFmpeg.git
Fixed-point AC-3 encoder renamed to ac3_fixed. Regression test acodec-ac3 renamed to acodec-ac3_fixed. Regression test lavf-rm changed to use ac3_fixed encoder. Originally committed as revision 26209 to svn://svn.ffmpeg.org/ffmpeg/trunkoldabi
Justin Ruggles
14 years ago
parent
6780f48846
commit
6fd96d1a85
12 changed files with 186 additions and 9 deletions
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/*
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* The simplest AC-3 encoder |
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* Copyright (c) 2000 Fabrice Bellard |
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* Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com> |
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* Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file |
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* floating-point AC-3 encoder. |
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*/ |
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#define CONFIG_AC3ENC_FLOAT 1 |
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#include "ac3enc.c" |
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/**
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* Finalize MDCT and free allocated memory. |
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*/ |
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static av_cold void mdct_end(AC3MDCTContext *mdct) |
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{ |
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ff_mdct_end(&mdct->fft); |
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av_freep(&mdct->window); |
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} |
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/**
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* Initialize MDCT tables. |
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* @param nbits log2(MDCT size) |
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*/ |
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static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct, |
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int nbits) |
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{ |
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float *window; |
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int n, n2; |
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n = 1 << nbits; |
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n2 = n >> 1; |
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window = av_malloc(n2 * sizeof(*window)); |
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if (!window) { |
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av_log(avctx, AV_LOG_ERROR, "Cannot allocate memory.\n"); |
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return AVERROR(ENOMEM); |
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} |
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ff_kbd_window_init(window, 5.0, n2); |
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mdct->window = window; |
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return ff_mdct_init(&mdct->fft, nbits, 0, -2.0 / n); |
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} |
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/**
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* Calculate a 512-point MDCT |
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* @param out 256 output frequency coefficients |
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* @param in 512 windowed input audio samples |
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*/ |
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static void mdct512(AC3MDCTContext *mdct, float *out, float *in) |
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{ |
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ff_mdct_calc(&mdct->fft, out, in); |
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} |
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/**
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* Apply KBD window to input samples prior to MDCT. |
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*/ |
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static void apply_window(float *output, const float *input, |
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const float *window, int n) |
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{ |
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int i; |
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int n2 = n >> 1; |
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for (i = 0; i < n2; i++) { |
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output[i] = input[i] * window[i]; |
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output[n-i-1] = input[n-i-1] * window[i]; |
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} |
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} |
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/**
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* Normalize the input samples to use the maximum available precision. |
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*/ |
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static int normalize_samples(AC3EncodeContext *s) |
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{ |
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/* Normalization is not needed for floating-point samples, so just return 0 */ |
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return 0; |
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} |
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AVCodec ac3_encoder = { |
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"ac3", |
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AVMEDIA_TYPE_AUDIO, |
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CODEC_ID_AC3, |
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sizeof(AC3EncodeContext), |
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ac3_encode_init, |
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ac3_encode_frame, |
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ac3_encode_close, |
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NULL, |
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.sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,AV_SAMPLE_FMT_NONE}, |
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.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"), |
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.channel_layouts = ac3_channel_layouts, |
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}; |
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@ -0,0 +1,46 @@ |
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/*
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* The simplest AC-3 encoder |
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* Copyright (c) 2000 Fabrice Bellard |
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* Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com> |
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* Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file |
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* floating-point AC-3 encoder header. |
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*/ |
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#ifndef AVCODEC_AC3ENC_FLOAT_H |
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#define AVCODEC_AC3ENC_FLOAT_H |
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#include "fft.h" |
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typedef float SampleType; |
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typedef float CoefType; |
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#define SCALE_COEF(a) SCALE_FLOAT((a), 24) |
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typedef struct AC3MDCTContext { |
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const float *window; ///< MDCT window function
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FFTContext fft; ///< FFT context for MDCT calculation
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} AC3MDCTContext; |
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#endif /* AVCODEC_AC3ENC_FLOAT_H */ |
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