FFmpeg
cngenc.c
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1 /*
2  * RFC 3389 comfort noise generator
3  * Copyright (c) 2012 Martin Storsjo
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <math.h>
23 
24 #include "libavutil/common.h"
25 #include "avcodec.h"
26 #include "encode.h"
27 #include "internal.h"
28 #include "lpc.h"
29 
30 typedef struct CNGContext {
32  int order;
34  double *ref_coef;
35 } CNGContext;
36 
38 {
39  CNGContext *p = avctx->priv_data;
40  ff_lpc_end(&p->lpc);
41  av_freep(&p->samples32);
42  av_freep(&p->ref_coef);
43  return 0;
44 }
45 
47 {
48  CNGContext *p = avctx->priv_data;
49  int ret;
50 
51  if (avctx->channels != 1) {
52  av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
53  return AVERROR(EINVAL);
54  }
55 
56  avctx->frame_size = 640;
57  p->order = 10;
58  if ((ret = ff_lpc_init(&p->lpc, avctx->frame_size, p->order, FF_LPC_TYPE_LEVINSON)) < 0)
59  return ret;
60  p->samples32 = av_malloc_array(avctx->frame_size, sizeof(*p->samples32));
61  p->ref_coef = av_malloc_array(p->order, sizeof(*p->ref_coef));
62  if (!p->samples32 || !p->ref_coef)
63  return AVERROR(ENOMEM);
64 
65  return 0;
66 }
67 
68 static int cng_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
69  const AVFrame *frame, int *got_packet_ptr)
70 {
71  CNGContext *p = avctx->priv_data;
72  int ret, i;
73  double energy = 0;
74  int qdbov;
75  int16_t *samples = (int16_t*) frame->data[0];
76 
77  if ((ret = ff_get_encode_buffer(avctx, avpkt, 1 + p->order, 0))) {
78  av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
79  return ret;
80  }
81 
82  for (i = 0; i < frame->nb_samples; i++) {
83  p->samples32[i] = samples[i];
84  energy += samples[i] * samples[i];
85  }
86  energy /= frame->nb_samples;
87  if (energy > 0) {
88  double dbov = 10 * log10(energy / 1081109975);
89  qdbov = av_clip_uintp2(-floor(dbov), 7);
90  } else {
91  qdbov = 127;
92  }
94  avpkt->data[0] = qdbov;
95  for (i = 0; i < p->order; i++)
96  avpkt->data[1 + i] = p->ref_coef[i] * 127 + 127;
97 
98  *got_packet_ptr = 1;
99  av_assert1(avpkt->size == 1 + p->order);
100 
101  return 0;
102 }
103 
105  .name = "comfortnoise",
106  .long_name = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
107  .type = AVMEDIA_TYPE_AUDIO,
109  .capabilities = AV_CODEC_CAP_DR1,
110  .priv_data_size = sizeof(CNGContext),
112  .encode2 = cng_encode_frame,
113  .close = cng_encode_close,
114  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
117 };
AVCodecContext::frame_size
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:1008
AVCodec
AVCodec.
Definition: codec.h:197
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
sample_fmts
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:948
av_clip_uintp2
#define av_clip_uintp2
Definition: common.h:120
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
encode.h
cng_encode_frame
static int cng_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
Definition: cngenc.c:68
lpc.h
LPCContext
Definition: lpc.h:52
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
ff_comfortnoise_encoder
const AVCodec ff_comfortnoise_encoder
Definition: cngenc.c:104
floor
static __device__ float floor(float a)
Definition: cuda_runtime.h:173
CNGContext::lpc
LPCContext lpc
Definition: cngenc.c:31
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
CNGContext::samples32
int32_t * samples32
Definition: cngenc.c:33
if
if(ret)
Definition: filter_design.txt:179
CNGContext
Definition: cngdec.c:32
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
AV_CODEC_ID_COMFORT_NOISE
@ AV_CODEC_ID_COMFORT_NOISE
Definition: codec_id.h:483
ff_lpc_calc_ref_coefs
int ff_lpc_calc_ref_coefs(LPCContext *s, const int32_t *samples, int order, double *ref)
Definition: lpc.c:160
ff_lpc_end
av_cold void ff_lpc_end(LPCContext *s)
Uninitialize LPCContext.
Definition: lpc.c:323
AVCodecContext::channels
int channels
number of audio channels
Definition: avcodec.h:989
cng_encode_init
static av_cold int cng_encode_init(AVCodecContext *avctx)
Definition: cngenc.c:46
i
int i
Definition: input.c:406
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:50
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
common.h
av_assert1
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:61
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
avcodec.h
CNGContext::order
int order
Definition: cngdec.c:35
ret
ret
Definition: filter_design.txt:187
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AVCodecContext
main external API structure.
Definition: avcodec.h:379
ff_get_encode_buffer
int ff_get_encode_buffer(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int flags)
Get a buffer for a packet.
Definition: encode.c:78
samples
Filter the word “frame” indicates either a video frame or a group of audio samples
Definition: filter_design.txt:8
cng_encode_close
static av_cold int cng_encode_close(AVCodecContext *avctx)
Definition: cngenc.c:37
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:406
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
CNGContext::ref_coef
double * ref_coef
Definition: cngenc.c:34
int32_t
int32_t
Definition: audioconvert.c:56
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
FF_LPC_TYPE_LEVINSON
@ FF_LPC_TYPE_LEVINSON
Levinson-Durbin recursion.
Definition: lpc.h:47
ff_lpc_init
av_cold int ff_lpc_init(LPCContext *s, int blocksize, int max_order, enum FFLPCType lpc_type)
Initialize LPCContext.
Definition: lpc.c:301