FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/pcm-dvd.c
Date: 2026-01-16 07:34:38
Exec Total Coverage
Lines: 109 146 74.7%
Functions: 4 4 100.0%
Branches: 37 57 64.9%
Line Branch Exec Source
1 /*
2 * LPCM codecs for PCM formats found in Video DVD streams
3 * Copyright (c) 2013 Christian Schmidt
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 /**
23 * @file
24 * LPCM codecs for PCM formats found in Video DVD streams
25 */
26
27 #include "avcodec.h"
28 #include "bytestream.h"
29 #include "codec_internal.h"
30 #include "decode.h"
31
32 typedef struct PCMDVDContext {
33 uint32_t last_header; // Cached header to see if parsing is needed
34 int block_size; // Size of a block of samples in bytes
35 int last_block_size; // Size of the last block of samples in bytes
36 int samples_per_block; // Number of samples per channel per block
37 int groups_per_block; // Number of 20/24-bit sample groups per block
38 int extra_sample_count; // Number of leftover samples in the buffer
39 uint8_t extra_samples[8 * 3 * 4]; // Space for leftover samples from a frame
40 // (8 channels, 3B/sample, 4 samples/block)
41 } PCMDVDContext;
42
43 24 static av_cold int pcm_dvd_decode_init(AVCodecContext *avctx)
44 {
45 24 PCMDVDContext *s = avctx->priv_data;
46
47 /* Invalid header to force parsing of the first header */
48 24 s->last_header = -1;
49
50 24 return 0;
51 }
52
53 584 static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header)
54 {
55 /* no traces of 44100 and 32000Hz in any commercial software or player */
56 static const uint32_t frequencies[4] = { 48000, 96000, 44100, 32000 };
57 584 PCMDVDContext *s = avctx->priv_data;
58 584 int header_int = (header[0] & 0xe0) | (header[1] << 8) | (header[2] << 16);
59 int channels;
60
61 /* early exit if the header didn't change apart from the frame number */
62
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 584 if (s->last_header == header_int)
63 560 return 0;
64 24 s->last_header = -1;
65
66
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 24 if (avctx->debug & FF_DEBUG_PICT_INFO)
67 ✗ av_log(avctx, AV_LOG_DEBUG, "pcm_dvd_parse_header: header = %02x%02x%02x\n",
68 ✗ header[0], header[1], header[2]);
69 /*
70 * header[0] emphasis (1), muse(1), reserved(1), frame number(5)
71 * header[1] quant (2), freq(2), reserved(1), channels(3)
72 * header[2] dynamic range control (0x80 = off)
73 */
74
75 /* Discard potentially existing leftover samples from old channel layout */
76 24 s->extra_sample_count = 0;
77
78 /* get the sample depth and derive the sample format from it */
79 24 avctx->bits_per_coded_sample = 16 + (header[1] >> 6 & 3) * 4;
80
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 24 if (avctx->bits_per_coded_sample == 28) {
81 ✗ av_log(avctx, AV_LOG_ERROR,
82 "PCM DVD unsupported sample depth %i\n",
83 avctx->bits_per_coded_sample);
84 ✗ return AVERROR_INVALIDDATA;
85 }
86 48 avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16
87
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 24 : AV_SAMPLE_FMT_S32;
88 24 avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
89
90 /* get the sample rate */
91 24 avctx->sample_rate = frequencies[header[1] >> 4 & 3];
92
93 /* get the number of channels */
94 24 channels = 1 + (header[1] & 7);
95
96 24 av_channel_layout_uninit(&avctx->ch_layout);
97 24 av_channel_layout_default(&avctx->ch_layout, channels);
98 /* calculate the bitrate */
99 24 avctx->bit_rate = channels *
100 24 avctx->sample_rate *
101 24 avctx->bits_per_coded_sample;
102
103 /* 4 samples form a group in 20/24-bit PCM on DVD Video.
104 * A block is formed by the number of groups that are
105 * needed to complete a set of samples for each channel. */
106
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 24 if (avctx->bits_per_coded_sample == 16) {
107 14 s->samples_per_block = 1;
108 14 s->block_size = channels * 2;
109 } else {
110
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 10 switch (channels) {
111 6 case 1:
112 case 2:
113 case 4:
114 /* one group has all the samples needed */
115 6 s->block_size = 4 * avctx->bits_per_coded_sample / 8;
116 6 s->samples_per_block = 4 / channels;
117 6 s->groups_per_block = 1;
118 6 break;
119 2 case 8:
120 /* two groups have all the samples needed */
121 2 s->block_size = 8 * avctx->bits_per_coded_sample / 8;
122 2 s->samples_per_block = 1;
123 2 s->groups_per_block = 2;
124 2 break;
125 2 default:
126 /* need channels groups */
127 2 s->block_size = 4 * channels *
128 2 avctx->bits_per_coded_sample / 8;
129 2 s->samples_per_block = 4;
130 2 s->groups_per_block = channels;
131 2 break;
132 }
133 }
134
135 24 if (avctx->debug & FF_DEBUG_PICT_INFO)
136 ff_dlog(avctx,
137 "pcm_dvd_parse_header: %d channels, %d bits per sample, %d Hz, %"PRId64" bit/s\n",
138 avctx->ch_layout.nb_channels, avctx->bits_per_coded_sample,
139 avctx->sample_rate, avctx->bit_rate);
140
141 24 s->last_header = header_int;
142
143 24 return 0;
144 }
145
146 697 static void *pcm_dvd_decode_samples(AVCodecContext *avctx, const uint8_t *src,
147 void *dst, int blocks)
148 {
149 697 PCMDVDContext *s = avctx->priv_data;
150 697 int16_t *dst16 = dst;
151 697 int32_t *dst32 = dst;
152 GetByteContext gb;
153 int i;
154 uint8_t t;
155
156 697 bytestream2_init(&gb, src, blocks * s->block_size);
157
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 697 switch (avctx->bits_per_coded_sample) {
158 220 case 16: {
159 #if HAVE_BIGENDIAN
160 bytestream2_get_buffer(&gb, (uint8_t*)dst16, blocks * s->block_size);
161 dst16 += blocks * s->block_size / 2;
162 #else
163 220 int samples = blocks * avctx->ch_layout.nb_channels;
164 do {
165 219441 *dst16++ = bytestream2_get_be16u(&gb);
166
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 219441 } while (--samples);
167 #endif
168 220 return dst16;
169 }
170 ✗ case 20:
171 ✗ if (avctx->ch_layout.nb_channels == 1) {
172 do {
173 ✗ for (i = 2; i; i--) {
174 ✗ dst32[0] = bytestream2_get_be16u(&gb) << 16;
175 ✗ dst32[1] = bytestream2_get_be16u(&gb) << 16;
176 ✗ t = bytestream2_get_byteu(&gb);
177 ✗ *dst32++ += (t & 0xf0) << 8;
178 ✗ *dst32++ += (t & 0x0f) << 12;
179 }
180 ✗ } while (--blocks);
181 } else {
182 do {
183 ✗ for (i = s->groups_per_block; i; i--) {
184 ✗ dst32[0] = bytestream2_get_be16u(&gb) << 16;
185 ✗ dst32[1] = bytestream2_get_be16u(&gb) << 16;
186 ✗ dst32[2] = bytestream2_get_be16u(&gb) << 16;
187 ✗ dst32[3] = bytestream2_get_be16u(&gb) << 16;
188 ✗ t = bytestream2_get_byteu(&gb);
189 ✗ *dst32++ += (t & 0xf0) << 8;
190 ✗ *dst32++ += (t & 0x0f) << 12;
191 ✗ t = bytestream2_get_byteu(&gb);
192 ✗ *dst32++ += (t & 0xf0) << 8;
193 ✗ *dst32++ += (t & 0x0f) << 12;
194 }
195 ✗ } while (--blocks);
196 }
197 ✗ return dst32;
198 477 case 24:
199
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 477 if (avctx->ch_layout.nb_channels == 1) {
200 do {
201
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 26418 for (i = 2; i; i--) {
202 17612 dst32[0] = bytestream2_get_be16u(&gb) << 16;
203 17612 dst32[1] = bytestream2_get_be16u(&gb) << 16;
204 17612 *dst32++ += bytestream2_get_byteu(&gb) << 8;
205 17612 *dst32++ += bytestream2_get_byteu(&gb) << 8;
206 }
207
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 8806 } while (--blocks);
208 } else {
209 do {
210
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 85596 for (i = s->groups_per_block; i; i--) {
211 51777 dst32[0] = bytestream2_get_be16u(&gb) << 16;
212 51777 dst32[1] = bytestream2_get_be16u(&gb) << 16;
213 51777 dst32[2] = bytestream2_get_be16u(&gb) << 16;
214 51777 dst32[3] = bytestream2_get_be16u(&gb) << 16;
215 51777 *dst32++ += bytestream2_get_byteu(&gb) << 8;
216 51777 *dst32++ += bytestream2_get_byteu(&gb) << 8;
217 51777 *dst32++ += bytestream2_get_byteu(&gb) << 8;
218 51777 *dst32++ += bytestream2_get_byteu(&gb) << 8;
219 }
220
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 33819 } while (--blocks);
221 }
222 477 return dst32;
223 ✗ default:
224 ✗ return NULL;
225 }
226 }
227
228 584 static int pcm_dvd_decode_frame(AVCodecContext *avctx, AVFrame *frame,
229 int *got_frame_ptr, AVPacket *avpkt)
230 {
231 584 const uint8_t *src = avpkt->data;
232 584 int buf_size = avpkt->size;
233 584 PCMDVDContext *s = avctx->priv_data;
234 int retval;
235 int blocks;
236 void *dst;
237
238
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 584 if (buf_size < 3) {
239 ✗ av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
240 ✗ return AVERROR_INVALIDDATA;
241 }
242
243
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 584 if ((retval = pcm_dvd_parse_header(avctx, src)))
244 ✗ return retval;
245
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 584 if (s->last_block_size && s->last_block_size != s->block_size) {
246 ✗ av_log(avctx, AV_LOG_WARNING, "block_size has changed %d != %d\n", s->last_block_size, s->block_size);
247 ✗ s->extra_sample_count = 0;
248 }
249 584 s->last_block_size = s->block_size;
250 584 src += 3;
251 584 buf_size -= 3;
252
253 584 blocks = (buf_size + s->extra_sample_count) / s->block_size;
254
255 /* get output buffer */
256 584 frame->nb_samples = blocks * s->samples_per_block;
257
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 584 if ((retval = ff_get_buffer(avctx, frame, 0)) < 0)
258 ✗ return retval;
259 584 dst = frame->data[0];
260
261 /* consume leftover samples from last packet */
262
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 584 if (s->extra_sample_count) {
263 113 int missing_samples = s->block_size - s->extra_sample_count;
264
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 113 if (buf_size >= missing_samples) {
265 113 memcpy(s->extra_samples + s->extra_sample_count, src,
266 missing_samples);
267 113 dst = pcm_dvd_decode_samples(avctx, s->extra_samples, dst, 1);
268 113 src += missing_samples;
269 113 buf_size -= missing_samples;
270 113 s->extra_sample_count = 0;
271 113 blocks--;
272 } else {
273 /* new packet still doesn't have enough samples */
274 ✗ memcpy(s->extra_samples + s->extra_sample_count, src, buf_size);
275 ✗ s->extra_sample_count += buf_size;
276 ✗ return avpkt->size;
277 }
278 }
279
280 /* decode remaining complete samples */
281
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 584 if (blocks) {
282 584 pcm_dvd_decode_samples(avctx, src, dst, blocks);
283 584 buf_size -= blocks * s->block_size;
284 }
285
286 /* store leftover samples */
287
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 584 if (buf_size) {
288 115 src += blocks * s->block_size;
289 115 memcpy(s->extra_samples, src, buf_size);
290 115 s->extra_sample_count = buf_size;
291 }
292
293 584 *got_frame_ptr = 1;
294
295 584 return avpkt->size;
296 }
297
298 const FFCodec ff_pcm_dvd_decoder = {
299 .p.name = "pcm_dvd",
300 CODEC_LONG_NAME("PCM signed 16|20|24-bit big-endian for DVD media"),
301 .p.type = AVMEDIA_TYPE_AUDIO,
302 .p.id = AV_CODEC_ID_PCM_DVD,
303 .priv_data_size = sizeof(PCMDVDContext),
304 .init = pcm_dvd_decode_init,
305 FF_CODEC_DECODE_CB(pcm_dvd_decode_frame),
306 .p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
307 AV_CODEC_CAP_DR1,
308 CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32),
309 };
310