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FFmpeg/libavcodec/ac3enc_float.c
Michael Niedermayer 80e4fe4063 Merge commit 'b5849f77095439e994b11c25e6063d443b36c228'
* commit 'b5849f77095439e994b11c25e6063d443b36c228': (21 commits)
  ac3enc: merge AC3MDCTContext with AC3EncodeContext.
  ac3enc: prefer passing AC3EncodeContext rather than AVCodecContext
  ac3enc: fix memleak
  mpeg1video: add CODEC_CAP_SLICE_THREADS.
  lavf: fix segfault in av_open_input_stream()
  mpegtsenc: set Random Access indicator on keyframe start packets
  lavf: Cleanup try_decode_frame() logic.
  Replace some gotos that lead to single return statements by direct return.
  build: move tests/seek_test.c to libavformat and reuse generic build rules
  mxfenc: include needed header for ff_iso8601_to_unix_time() prototype
  Add a check for strptime().
  lavf: factor out conversion of ISO8601 string to unix time
  wav: parse 'bext' metadata
  wav: keep parsing until EOF if the input is seekable and we know the size of the data tag
  wav: Refactor the tag checking into a switch statement
  wav: make sure neither data_size nor sample_count is negative.
  wav: refactor the 'fmt ' tag search and parsing.
  wav: add an option for writing BEXT chunk
  ffmpeg: get rid of a pointless limit on number of streams.
  ffmpeg: remove an unused define.
  ...

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2011-07-14 02:24:10 +02:00

138 lines
3.5 KiB
C

/*
* 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(AC3EncodeContext *s)
{
ff_mdct_end(&s->mdct);
av_freep(&s->mdct_window);
}
/**
* Initialize MDCT tables.
* @param nbits log2(MDCT size)
*/
av_cold int ff_ac3_float_mdct_init(AC3EncodeContext *s)
{
float *window;
int i, n, n2;
n = 1 << 9;
n2 = n >> 1;
window = av_malloc(n * 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, n2);
for (i = 0; i < n2; i++)
window[n-1-i] = window[i];
s->mdct_window = window;
return ff_mdct_init(&s->mdct, 9, 0, -2.0 / n);
}
/**
* Apply KBD window to input samples prior to MDCT.
*/
static void apply_window(DSPContext *dsp, float *output, const float *input,
const float *window, unsigned int len)
{
dsp->vector_fmul(output, input, window, len);
}
/**
* Normalize the input samples.
* Not needed for the floating-point encoder.
*/
static int normalize_samples(AC3EncodeContext *s)
{
return 0;
}
/**
* Scale MDCT coefficients from float to 24-bit fixed-point.
*/
static void 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);
}
/**
* Clip MDCT coefficients to allowable range.
*/
static void clip_coefficients(DSPContext *dsp, float *coef, unsigned int len)
{
dsp->vector_clipf(coef, coef, COEF_MIN, COEF_MAX, len);
}
#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_float_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