/*
- * The simplest AC3 encoder
- * Copyright (c) 2000 Fabrice Bellard.
+ * The simplest AC-3 encoder
+ * Copyright (c) 2000 Fabrice Bellard
*
* This file is part of FFmpeg.
*
*/
/**
- * @file ac3enc.c
- * The simplest AC3 encoder.
+ * @file libavcodec/ac3enc.c
+ * The simplest AC-3 encoder.
*/
//#define DEBUG
//#define DEBUG_BITALLOC
+#include "libavutil/crc.h"
#include "avcodec.h"
-#include "bitstream.h"
-#include "crc.h"
+#include "libavutil/common.h" /* for av_reverse */
+#include "put_bits.h"
#include "ac3.h"
+#include "audioconvert.h"
typedef struct AC3EncodeContext {
PutBitContext pb;
int nb_channels;
int nb_all_channels;
int lfe_channel;
+ const uint8_t *channel_map;
int bit_rate;
unsigned int sample_rate;
unsigned int bitstream_id;
static int16_t costab[64];
static int16_t sintab[64];
-static int16_t fft_rev[512];
static int16_t xcos1[128];
static int16_t xsin1[128];
/* new exponents are sent if their Norm 1 exceed this number */
#define EXP_DIFF_THRESHOLD 1000
-static void fft_init(int ln);
-
static inline int16_t fix15(float a)
{
int v;
short re,im;
} IComplex;
-static void fft_init(int ln)
+static av_cold void fft_init(int ln)
{
- int i, j, m, n;
+ int i, n;
float alpha;
n = 1 << ln;
costab[i] = fix15(cos(alpha));
sintab[i] = fix15(sin(alpha));
}
-
- for(i=0;i<n;i++) {
- m=0;
- for(j=0;j<ln;j++) {
- m |= ((i >> j) & 1) << (ln-j-1);
- }
- fft_rev[i]=m;
- }
}
/* butter fly op */
qim = (by - ay) >> 1;\
}
-#define MUL16(a,b) ((a) * (b))
-
#define CMUL(pre, pim, are, aim, bre, bim) \
{\
pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15;\
/* reverse */
for(j=0;j<np;j++) {
- int k;
- IComplex tmp;
- k = fft_rev[j];
- if (k < j) {
- tmp = z[k];
- z[k] = z[j];
- z[j] = tmp;
- }
+ int k = av_reverse[j] >> (8 - ln);
+ if (k < j)
+ FFSWAP(IComplex, z[k], z[j]);
}
/* pass 0 */
exp_strategy[0][ch] = EXP_NEW;
for(i=1;i<NB_BLOCKS;i++) {
exp_diff = calc_exp_diff(exp[i][ch], exp[i-1][ch], N/2);
-#ifdef DEBUG
- av_log(NULL, AV_LOG_DEBUG, "exp_diff=%d\n", exp_diff);
-#endif
+ dprintf(NULL, "exp_diff=%d\n", exp_diff);
if (exp_diff > EXP_DIFF_THRESHOLD)
exp_strategy[i][ch] = EXP_NEW;
else
for(ch=0;ch<s->nb_all_channels;ch++) {
ff_ac3_bit_alloc_calc_bap(mask[i][ch], psd[i][ch], 0,
s->nb_coefs[ch], snr_offset,
- s->bit_alloc.floor, bap[i][ch]);
+ s->bit_alloc.floor, ff_ac3_bap_tab,
+ bap[i][ch]);
frame_bits += compute_mantissa_size(s, bap[i][ch],
s->nb_coefs[ch]);
}
uint8_t bap1[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50];
- static int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
+ static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
/* init default parameters */
s->slow_decay_code = 2;
return 0;
}
-static int AC3_encode_init(AVCodecContext *avctx)
+static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
+ int64_t *channel_layout)
+{
+ int ch_layout;
+
+ if (channels < 1 || channels > AC3_MAX_CHANNELS)
+ return -1;
+ if ((uint64_t)*channel_layout > 0x7FF)
+ return -1;
+ ch_layout = *channel_layout;
+ if (!ch_layout)
+ ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
+ if (avcodec_channel_layout_num_channels(ch_layout) != channels)
+ return -1;
+
+ s->lfe = !!(ch_layout & CH_LOW_FREQUENCY);
+ s->nb_all_channels = channels;
+ s->nb_channels = channels - s->lfe;
+ s->lfe_channel = s->lfe ? s->nb_channels : -1;
+ if (s->lfe)
+ ch_layout -= CH_LOW_FREQUENCY;
+
+ switch (ch_layout) {
+ case CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
+ case CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
+ case CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
+ case CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
+ case CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
+ case CH_LAYOUT_QUAD:
+ case CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
+ case CH_LAYOUT_5POINT0:
+ case CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
+ default:
+ return -1;
+ }
+
+ s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe];
+ *channel_layout = ch_layout;
+ if (s->lfe)
+ *channel_layout |= CH_LOW_FREQUENCY;
+
+ return 0;
+}
+
+static av_cold int AC3_encode_init(AVCodecContext *avctx)
{
int freq = avctx->sample_rate;
int bitrate = avctx->bit_rate;
- int channels = avctx->channels;
AC3EncodeContext *s = avctx->priv_data;
int i, j, ch;
float alpha;
- static const uint8_t channel_mode_defs[6] = {
- 0x01, /* C */
- 0x02, /* L R */
- 0x03, /* L C R */
- 0x06, /* L R SL SR */
- 0x07, /* L C R SL SR */
- 0x07, /* L C R SL SR (+LFE) */
- };
+ int bw_code;
avctx->frame_size = AC3_FRAME_SIZE;
ac3_common_init();
- /* number of channels */
- if (channels < 1 || channels > 6)
+ if (!avctx->channel_layout) {
+ av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
+ "encoder will guess the layout, but it "
+ "might be incorrect.\n");
+ }
+ if (set_channel_info(s, avctx->channels, &avctx->channel_layout)) {
+ av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
return -1;
- s->channel_mode = channel_mode_defs[channels - 1];
- s->lfe = (channels == 6) ? 1 : 0;
- s->nb_all_channels = channels;
- s->nb_channels = channels > 5 ? 5 : channels;
- s->lfe_channel = s->lfe ? 5 : -1;
+ }
/* frequency */
for(i=0;i<3;i++) {
s->bitstream_mode = 0; /* complete main audio service */
/* bitrate & frame size */
- bitrate /= 1000;
for(i=0;i<19;i++) {
- if ((ff_ac3_bitrate_tab[i] >> s->sr_shift) == bitrate)
+ if ((ff_ac3_bitrate_tab[i] >> s->sr_shift)*1000 == bitrate)
break;
}
if (i == 19)
s->frame_size = s->frame_size_min;
/* bit allocation init */
+ if(avctx->cutoff) {
+ /* calculate bandwidth based on user-specified cutoff frequency */
+ int cutoff = av_clip(avctx->cutoff, 1, s->sample_rate >> 1);
+ int fbw_coeffs = cutoff * 512 / s->sample_rate;
+ bw_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
+ } else {
+ /* use default bandwidth setting */
+ /* XXX: should compute the bandwidth according to the frame
+ size, so that we avoid annoying high frequency artifacts */
+ bw_code = 50;
+ }
for(ch=0;ch<s->nb_channels;ch++) {
/* bandwidth for each channel */
- /* XXX: should compute the bandwidth according to the frame
- size, so that we avoid anoying high freq artefacts */
- s->chbwcod[ch] = 50; /* sample bandwidth as mpeg audio layer 2 table 0 */
- s->nb_coefs[ch] = ((s->chbwcod[ch] + 12) * 3) + 37;
+ s->chbwcod[ch] = bw_code;
+ s->nb_coefs[ch] = bw_code * 3 + 73;
}
if (s->lfe) {
s->nb_coefs[s->lfe_channel] = 7; /* fixed */
return 0;
}
-/* output the AC3 frame header */
+/* output the AC-3 frame header */
static void output_frame_header(AC3EncodeContext *s, unsigned char *frame)
{
init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
return v & ((1 << qbits)-1);
}
-/* Output one audio block. There are NB_BLOCKS audio blocks in one AC3
+/* Output one audio block. There are NB_BLOCKS audio blocks in one AC-3
frame */
static void output_audio_block(AC3EncodeContext *s,
uint8_t exp_strategy[AC3_MAX_CHANNELS],
flush_put_bits(&s->pb);
/* add zero bytes to reach the frame size */
frame = s->pb.buf;
- n = 2 * s->frame_size - (pbBufPtr(&s->pb) - frame) - 2;
+ n = 2 * s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
assert(n >= 0);
if(n>0)
- memset(pbBufPtr(&s->pb), 0, n);
+ memset(put_bits_ptr(&s->pb), 0, n);
/* Now we must compute both crcs : this is not so easy for crc1
because it is at the beginning of the data... */
frame_size_58 = (frame_size >> 1) + (frame_size >> 3);
- crc1 = bswap_16(av_crc(av_crc8005, 0, frame + 4, 2 * frame_size_58 - 4));
+ crc1 = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
+ frame + 4, 2 * frame_size_58 - 4));
/* XXX: could precompute crc_inv */
crc_inv = pow_poly((CRC16_POLY >> 1), (16 * frame_size_58) - 16, CRC16_POLY);
crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
AV_WB16(frame+2,crc1);
- crc2 = bswap_16(av_crc(av_crc8005, 0, frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2));
+ crc2 = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
+ frame + 2 * frame_size_58,
+ (frame_size - frame_size_58) * 2 - 2));
AV_WB16(frame+2*frame_size-2,crc2);
// printf("n=%d frame_size=%d\n", n, frame_size);
frame_bits = 0;
for(ch=0;ch<s->nb_all_channels;ch++) {
+ int ich = s->channel_map[ch];
/* fixed mdct to the six sub blocks & exponent computation */
for(i=0;i<NB_BLOCKS;i++) {
int16_t *sptr;
int sinc;
/* compute input samples */
- memcpy(input_samples, s->last_samples[ch], N/2 * sizeof(int16_t));
+ memcpy(input_samples, s->last_samples[ich], N/2 * sizeof(int16_t));
sinc = s->nb_all_channels;
- sptr = samples + (sinc * (N/2) * i) + ch;
+ sptr = samples + (sinc * (N/2) * i) + ich;
for(j=0;j<N/2;j++) {
v = *sptr;
input_samples[j + N/2] = v;
- s->last_samples[ch][j] = v;
+ s->last_samples[ich][j] = v;
sptr += sinc;
}
}
/* adjust for fractional frame sizes */
- while(s->bits_written >= s->bit_rate*1000 && s->samples_written >= s->sample_rate) {
- s->bits_written -= s->bit_rate*1000;
+ while(s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
+ s->bits_written -= s->bit_rate;
s->samples_written -= s->sample_rate;
}
- s->frame_size = s->frame_size_min + (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate*1000);
+ s->frame_size = s->frame_size_min + (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
s->bits_written += s->frame_size * 16;
s->samples_written += AC3_FRAME_SIZE;
return output_frame_end(s);
}
-static int AC3_encode_close(AVCodecContext *avctx)
+static av_cold int AC3_encode_close(AVCodecContext *avctx)
{
av_freep(&avctx->coded_frame);
return 0;
AVCodec ac3_encoder = {
"ac3",
- CODEC_TYPE_AUDIO,
+ AVMEDIA_TYPE_AUDIO,
CODEC_ID_AC3,
sizeof(AC3EncodeContext),
AC3_encode_init,
AC3_encode_frame,
AC3_encode_close,
NULL,
+ .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
+ .channel_layouts = (const int64_t[]){
+ CH_LAYOUT_MONO,
+ CH_LAYOUT_STEREO,
+ CH_LAYOUT_2_1,
+ CH_LAYOUT_SURROUND,
+ CH_LAYOUT_2_2,
+ CH_LAYOUT_QUAD,
+ CH_LAYOUT_4POINT0,
+ CH_LAYOUT_5POINT0,
+ CH_LAYOUT_5POINT0_BACK,
+ (CH_LAYOUT_MONO | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_STEREO | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_2_1 | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_SURROUND | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_2_2 | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_QUAD | CH_LOW_FREQUENCY),
+ (CH_LAYOUT_4POINT0 | CH_LOW_FREQUENCY),
+ CH_LAYOUT_5POINT1,
+ CH_LAYOUT_5POINT1_BACK,
+ 0 },
};
projects / ffmpeg / blobdiff