ra144dec.c
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1 /*
2  * Real Audio 1.0 (14.4K)
3  *
4  * Copyright (c) 2008 Vitor Sessak
5  * Copyright (c) 2003 Nick Kurshev
6  * Based on public domain decoder at http://www.honeypot.net/audio
7  *
8  * This file is part of Libav.
9  *
10  * Libav is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * Libav is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with Libav; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "libavutil/intmath.h"
26 #include "avcodec.h"
27 #include "internal.h"
28 #include "get_bits.h"
29 #include "ra144.h"
30 
31 
33 {
34  RA144Context *ractx = avctx->priv_data;
35 
36  ractx->avctx = avctx;
37 
38  ractx->lpc_coef[0] = ractx->lpc_tables[0];
39  ractx->lpc_coef[1] = ractx->lpc_tables[1];
40 
42 
44  avctx->coded_frame = &ractx->frame;
45 
46  return 0;
47 }
48 
49 static void do_output_subblock(RA144Context *ractx, const uint16_t *lpc_coefs,
50  int gval, GetBitContext *gb)
51 {
52  int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
53  int gain = get_bits(gb, 8);
54  int cb1_idx = get_bits(gb, 7);
55  int cb2_idx = get_bits(gb, 7);
56 
57  ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval,
58  gain);
59 }
60 
62 static int ra144_decode_frame(AVCodecContext * avctx, void *data,
63  int *got_frame_ptr, AVPacket *avpkt)
64 {
65  const uint8_t *buf = avpkt->data;
66  int buf_size = avpkt->size;
67  static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
68  unsigned int refl_rms[NBLOCKS]; // RMS of the reflection coefficients
69  uint16_t block_coefs[NBLOCKS][LPC_ORDER]; // LPC coefficients of each sub-block
70  unsigned int lpc_refl[LPC_ORDER]; // LPC reflection coefficients of the frame
71  int i, j;
72  int ret;
73  int16_t *samples;
74  unsigned int energy;
75 
76  RA144Context *ractx = avctx->priv_data;
77  GetBitContext gb;
78 
79  /* get output buffer */
80  ractx->frame.nb_samples = NBLOCKS * BLOCKSIZE;
81  if ((ret = ff_get_buffer(avctx, &ractx->frame)) < 0) {
82  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
83  return ret;
84  }
85  samples = (int16_t *)ractx->frame.data[0];
86 
87  if(buf_size < FRAMESIZE) {
88  av_log(avctx, AV_LOG_ERROR,
89  "Frame too small (%d bytes). Truncated file?\n", buf_size);
90  *got_frame_ptr = 0;
91  return buf_size;
92  }
93  init_get_bits(&gb, buf, FRAMESIZE * 8);
94 
95  for (i = 0; i < LPC_ORDER; i++)
96  lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])];
97 
98  ff_eval_coefs(ractx->lpc_coef[0], lpc_refl);
99  ractx->lpc_refl_rms[0] = ff_rms(lpc_refl);
100 
101  energy = ff_energy_tab[get_bits(&gb, 5)];
102 
103  refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
104  refl_rms[1] = ff_interp(ractx, block_coefs[1], 2,
105  energy <= ractx->old_energy,
106  ff_t_sqrt(energy*ractx->old_energy) >> 12);
107  refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy);
108  refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy);
109 
110  ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]);
111 
112  for (i=0; i < NBLOCKS; i++) {
113  do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
114 
115  for (j=0; j < BLOCKSIZE; j++)
116  *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2);
117  }
118 
119  ractx->old_energy = energy;
120  ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
121 
122  FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
123 
124  *got_frame_ptr = 1;
125  *(AVFrame *)data = ractx->frame;
126 
127  return FRAMESIZE;
128 }
129 
131  .name = "real_144",
132  .type = AVMEDIA_TYPE_AUDIO,
133  .id = CODEC_ID_RA_144,
134  .priv_data_size = sizeof(RA144Context),
137  .capabilities = CODEC_CAP_DR1,
138  .long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
139 };
unsigned int lpc_tables[2][10]
Definition: ra144.h:42
int ff_t_sqrt(unsigned int x)
Evaluate sqrt(x << 24).
Definition: ra144.c:1617
Audio Video Frame.
Definition: avcodec.h:985
const int16_t *const ff_lpc_refl_cb[10]
Definition: ra144.c:1501
static short * samples
Definition: ffmpeg.c:233
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:237
AVFrame * coded_frame
the picture in the bitstream
Definition: avcodec.h:2000
int size
Definition: avcodec.h:909
signed 16 bits
Definition: samplefmt.h:30
AVCodec.
Definition: avcodec.h:3189
#define NBLOCKS
number of subblocks within a block
Definition: ra144.h:28
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:228
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1464
#define av_cold
Definition: attributes.h:71
unsigned int lpc_refl_rms[2]
Definition: ra144.h:48
unsigned int ff_rms(const int *data)
Definition: ra144.c:1628
const char data[16]
Definition: mxf.c:60
uint8_t * data
Definition: avcodec.h:908
bitstream reader API header.
#define FRAMESIZE
size of encoded frame
Definition: ra144.h:32
void ff_subblock_synthesis(RA144Context *ractx, const uint16_t *lpc_coefs, int cba_idx, int cb1_idx, int cb2_idx, int gval, int gain)
Definition: ra144.c:1689
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:336
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:719
AVCodecContext * avctx
Definition: ra144.h:36
static av_cold int ra144_decode_init(AVCodecContext *avctx)
Definition: ra144dec.c:32
unsigned int * lpc_coef[2]
LPC coefficients: lpc_coef[0] is the coefficients of the current frame and lpc_coef[1] of the previou...
Definition: ra144.h:46
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:191
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:140
const char * name
Name of the codec implementation.
Definition: avcodec.h:3196
int ff_interp(RA144Context *ractx, int16_t *out, int a, int copyold, int energy)
Definition: ra144.c:1649
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame)
Definition: utils.c:1867
AVFrame frame
Definition: ra144.h:37
void ff_int_to_int16(int16_t *out, const int *inp)
Definition: ra144.c:1605
#define BLOCKSIZE
subblock size in 16-bit words
Definition: ra144.h:29
void ff_eval_coefs(int *coefs, const int *refl)
Evaluate the LPC filter coefficients from the reflection coefficients.
Definition: ra144.c:1585
external API header
main external API structure.
Definition: avcodec.h:1329
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:111
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:354
AVCodec ff_ra_144_decoder
Definition: ra144dec.c:130
unsigned int ff_rescale_rms(unsigned int rms, unsigned int energy)
Definition: ra144.c:1670
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: avcodec.h:997
common internal api header.
unsigned int old_energy
previous frame energy
Definition: ra144.h:40
const int16_t ff_energy_tab[32]
Definition: ra144.c:1439
int16_t curr_sblock[50]
The current subblock padded by the last 10 values of the previous one.
Definition: ra144.h:53
static void do_output_subblock(RA144Context *ractx, const uint16_t *lpc_coefs, int gval, GetBitContext *gb)
Definition: ra144dec.c:49
void * priv_data
Definition: avcodec.h:1531
void avcodec_get_frame_defaults(AVFrame *pic)
Set the fields of the given AVFrame to default values.
Definition: utils.c:609
#define LPC_ORDER
order of LPC filter
Definition: ra144.h:33
static int ra144_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Uncompress one block (20 bytes -> 160*2 bytes).
Definition: ra144dec.c:62
#define FFSWAP(type, a, b)
Definition: common.h:58
static const int sizes[][2]
Definition: img2.c:91
int nb_samples
number of audio samples (per channel) described by this frame
Definition: avcodec.h:1265