mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-07 11:13:41 +02:00
034fc7bf12
* qatar/master: (22 commits)
configure: enable memalign_hack automatically when needed
swscale: unbreak the build on non-x86 systems.
swscale: remove if(bitexact) branch from functions.
swscale: remove if(canMMX2BeUsed) conditional.
swscale: remove swScale_{c,MMX,MMX2} duplication.
swscale: use emms_c().
Move emms_c() from libavcodec to libavutil.
tiff: set palette in the context when specified in TIFF_PAL tag
rtsp: use strtoul to parse rtptime and seq values.
pgssubdec: fix incorrect colors.
dvdsubdec: fix incorrect colors.
ape: Allow demuxing of files with metadata tags.
swscale: remove dead macro WRITEBGR24OLD.
swscale: remove AMD3DNOW "optimizations".
swscale: remove duplicate code in ppc/ subdirectory.
swscale: remove duplicated x86/ functions.
swscale: force --enable-runtime-cpudetect and remove SWS_CPU_CAPS_*.
vsrc_buffer.h: add file doxy
vsrc_buffer: tweak error message in init()
msmpeg4: reindent.
...
Merged-by: Michael Niedermayer <michaelni@gmx.at>
126 lines
3.3 KiB
C
126 lines
3.3 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
|
|
* fixed-point AC-3 encoder.
|
|
*/
|
|
|
|
#define CONFIG_FFT_FLOAT 0
|
|
#undef CONFIG_AC3ENC_FLOAT
|
|
#include "ac3enc.c"
|
|
|
|
|
|
/**
|
|
* Finalize MDCT and free allocated memory.
|
|
*/
|
|
static av_cold void mdct_end(AC3MDCTContext *mdct)
|
|
{
|
|
ff_mdct_end(&mdct->fft);
|
|
}
|
|
|
|
|
|
/**
|
|
* Initialize MDCT tables.
|
|
* @param nbits log2(MDCT size)
|
|
*/
|
|
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
|
|
int nbits)
|
|
{
|
|
int ret = ff_mdct_init(&mdct->fft, nbits, 0, -1.0);
|
|
mdct->window = ff_ac3_window;
|
|
return ret;
|
|
}
|
|
|
|
|
|
/**
|
|
* Apply KBD window to input samples prior to MDCT.
|
|
*/
|
|
static void apply_window(DSPContext *dsp, int16_t *output, const int16_t *input,
|
|
const int16_t *window, unsigned int len)
|
|
{
|
|
dsp->apply_window_int16(output, input, window, len);
|
|
}
|
|
|
|
|
|
/**
|
|
* Calculate the log2() of the maximum absolute value in an array.
|
|
* @param tab input array
|
|
* @param n number of values in the array
|
|
* @return log2(max(abs(tab[])))
|
|
*/
|
|
static int log2_tab(AC3EncodeContext *s, int16_t *src, int len)
|
|
{
|
|
int v = s->ac3dsp.ac3_max_msb_abs_int16(src, len);
|
|
return av_log2(v);
|
|
}
|
|
|
|
|
|
/**
|
|
* Normalize the input samples to use the maximum available precision.
|
|
* This assumes signed 16-bit input samples.
|
|
*
|
|
* @return exponent shift
|
|
*/
|
|
static int normalize_samples(AC3EncodeContext *s)
|
|
{
|
|
int v = 14 - log2_tab(s, s->windowed_samples, AC3_WINDOW_SIZE);
|
|
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 < AC3_MAX_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]);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
AVCodec ff_ac3_fixed_encoder = {
|
|
"ac3_fixed",
|
|
AVMEDIA_TYPE_AUDIO,
|
|
CODEC_ID_AC3,
|
|
sizeof(AC3EncodeContext),
|
|
ac3_encode_init,
|
|
ac3_encode_frame,
|
|
ac3_encode_close,
|
|
NULL,
|
|
.sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,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,
|
|
};
|