FFmpeg
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:1620
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1483
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:3494
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2267
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:2238
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:1500
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 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:1482
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2794
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 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:3501
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:1016
int extra_sample_count
Definition: pcm-dvd.c:38
int32_t
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
#define s(width, name)
Definition: cbs_vp9.c:257
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2250
int frame_size
Definition: mxfenc.c:2150
Libavcodec external API header.
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int sample_rate
samples per second
Definition: avcodec.h:2230
main external API structure.
Definition: avcodec.h:1570
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:1597
AVCodec ff_pcm_dvd_encoder
Definition: pcm-dvdenc.c:178
int channels
number of audio channels
Definition: avcodec.h:2231
Filter the word “frame” indicates either a video frame or a group of audio samples
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
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
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1459
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:1475