FFmpeg  4.2.1
pcm-dvdenc.c
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1 /*
2  * LPCM codecs for PCM formats found in Video DVD streams
3  * Copyright (c) 2018 Paul B Mahol
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 "avcodec.h"
23 #include "bytestream.h"
24 #include "internal.h"
25 
26 typedef struct PCMDVDContext {
27  uint8_t header[3]; // Header added to every frame
28  int block_size; // Size of a block of samples in bytes
29  int samples_per_block; // Number of samples per channel per block
30  int groups_per_block; // Number of 20/24-bit sample groups per block
31  uint8_t *extra_samples; // Pointer to leftover samples from a frame
32  int extra_sample_count; // Number of leftover samples in the buffer
34 
36 {
37  PCMDVDContext *s = avctx->priv_data;
38  int quant, freq, frame_size;
39 
40  switch (avctx->sample_rate) {
41  case 48000:
42  freq = 0;
43  break;
44  case 96000:
45  freq = 1;
46  break;
47  }
48 
49  switch (avctx->sample_fmt) {
50  case AV_SAMPLE_FMT_S16:
51  avctx->bits_per_coded_sample = 16;
52  quant = 0;
53  break;
54  case AV_SAMPLE_FMT_S32:
55  avctx->bits_per_coded_sample = 24;
56  quant = 2;
57  break;
58  }
59 
60  avctx->bits_per_coded_sample = 16 + quant * 4;
61  avctx->block_align = avctx->channels * avctx->bits_per_coded_sample / 8;
62  avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
63  if (avctx->bit_rate > 9800000) {
64  av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
65  return AVERROR(EINVAL);
66  }
67 
68  if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
69  s->samples_per_block = 1;
70  s->block_size = avctx->channels * 2;
71  frame_size = 2008 / s->block_size;
72  } else {
73  switch (avctx->channels) {
74  case 1:
75  case 2:
76  case 4:
77  /* one group has all the samples needed */
78  s->block_size = 4 * avctx->bits_per_coded_sample / 8;
79  s->samples_per_block = 4 / avctx->channels;
80  s->groups_per_block = 1;
81  break;
82  case 8:
83  /* two groups have all the samples needed */
84  s->block_size = 8 * avctx->bits_per_coded_sample / 8;
85  s->samples_per_block = 1;
86  s->groups_per_block = 2;
87  break;
88  default:
89  /* need avctx->channels groups */
90  s->block_size = 4 * avctx->channels *
91  avctx->bits_per_coded_sample / 8;
92  s->samples_per_block = 4;
93  s->groups_per_block = avctx->channels;
94  break;
95  }
96 
97  frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
98  }
99 
100  s->header[0] = 0x0c;
101  s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
102  s->header[2] = 0x80;
103 
104  if (!avctx->frame_size)
105  avctx->frame_size = frame_size;
106 
107  return 0;
108 }
109 
110 static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
111  const AVFrame *frame, int *got_packet_ptr)
112 {
113  PCMDVDContext *s = avctx->priv_data;
114  int samples = frame->nb_samples * avctx->channels;
115  int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
116  int blocks = (pkt_size - 3) / s->block_size;
117  const int16_t *src16;
118  const int32_t *src32;
119  PutByteContext pb;
120  int ret;
121 
122  if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
123  return ret;
124 
125  memcpy(avpkt->data, s->header, 3);
126 
127  src16 = (const int16_t *)frame->data[0];
128  src32 = (const int32_t *)frame->data[0];
129 
130  bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
131 
132  switch (avctx->sample_fmt) {
133  case AV_SAMPLE_FMT_S16:
134  do {
135  bytestream2_put_be16(&pb, *src16++);
136  } while (--samples);
137  break;
138  case AV_SAMPLE_FMT_S32:
139  if (avctx->channels == 1) {
140  do {
141  for (int i = 2; i; i--) {
142  bytestream2_put_be16(&pb, src32[0] >> 16);
143  bytestream2_put_be16(&pb, src32[1] >> 16);
144  bytestream2_put_byte(&pb, (*src32++) >> 24);
145  bytestream2_put_byte(&pb, (*src32++) >> 24);
146  }
147  } while (--blocks);
148  } else {
149  do {
150  for (int i = s->groups_per_block; i; i--) {
151  bytestream2_put_be16(&pb, src32[0] >> 16);
152  bytestream2_put_be16(&pb, src32[1] >> 16);
153  bytestream2_put_be16(&pb, src32[2] >> 16);
154  bytestream2_put_be16(&pb, src32[3] >> 16);
155  bytestream2_put_byte(&pb, (*src32++) >> 24);
156  bytestream2_put_byte(&pb, (*src32++) >> 24);
157  bytestream2_put_byte(&pb, (*src32++) >> 24);
158  bytestream2_put_byte(&pb, (*src32++) >> 24);
159  }
160  } while (--blocks);
161  }
162  break;
163  }
164 
165  avpkt->pts = frame->pts;
166  avpkt->size = pkt_size;
167  avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
168  *got_packet_ptr = 1;
169 
170  return 0;
171 }
172 
174 {
175  return 0;
176 }
177 
179  .name = "pcm_dvd",
180  .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
181  .type = AVMEDIA_TYPE_AUDIO,
182  .id = AV_CODEC_ID_PCM_DVD,
183  .priv_data_size = sizeof(PCMDVDContext),
185  .close = pcm_dvd_encode_close,
186  .encode2 = pcm_dvd_encode_frame,
187  .capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME,
188  .supported_samplerates = (const int[]) { 48000, 96000, 0},
189  .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
193  0 },
194  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
197 };
uint8_t header[3]
Definition: pcm-dvdenc.c:27
#define AV_CH_LAYOUT_7POINT1
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
int64_t bit_rate
the average bitrate
Definition: avcodec.h:1615
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1478
static av_always_inline void bytestream2_init_writer(PutByteContext *p, uint8_t *buf, int buf_size)
Definition: bytestream.h:143
#define AV_CH_LAYOUT_STEREO
AVCodec.
Definition: avcodec.h:3481
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2262
int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size)
Check AVPacket size and/or allocate data.
Definition: encode.c:32
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2233
uint8_t
#define av_cold
Definition: attributes.h:82
static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
Definition: pcm-dvdenc.c:35
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1495
static av_cold int pcm_dvd_encode_close(AVCodecContext *avctx)
Definition: pcm-dvdenc.c:173
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:388
static AVFrame * frame
static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
Definition: pcm-dvdenc.c:110
uint8_t * data
Definition: avcodec.h:1477
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2789
signed 32 bits
Definition: samplefmt.h:62
#define FFALIGN(x, a)
Definition: macros.h:48
#define av_log(a,...)
#define AV_CH_LAYOUT_5POINT1
uint8_t * extra_samples
Definition: pcm-dvd.c:37
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int groups_per_block
Definition: pcm-dvd.c:36
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
const char * name
Name of the codec implementation.
Definition: avcodec.h:3488
int samples_per_block
Definition: pcm-dvd.c:35
#define AV_CODEC_CAP_SMALL_LAST_FRAME
Codec can be fed a final frame with a smaller size.
Definition: avcodec.h:1011
int extra_sample_count
Definition: pcm-dvd.c:38
int32_t
#define s(width, name)
Definition: cbs_vp9.c:257
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2245
int frame_size
Definition: mxfenc.c:2215
Libavcodec external API header.
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int sample_rate
samples per second
Definition: avcodec.h:2225
main external API structure.
Definition: avcodec.h:1565
const uint8_t * quant
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
common internal api header.
signed 16 bits
Definition: samplefmt.h:61
void * priv_data
Definition: avcodec.h:1592
AVCodec ff_pcm_dvd_encoder
Definition: pcm-dvdenc.c:178
int channels
number of audio channels
Definition: avcodec.h:2226
static av_always_inline int64_t ff_samples_to_time_base(AVCodecContext *avctx, int64_t samples)
Rescale from sample rate to AVCodecContext.time_base.
Definition: internal.h:288
int block_size
Definition: pcm-dvd.c:33
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1454
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:361
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470