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1 /*
2  * Digital Speech Standard (DSS) demuxer
3  * Copyright (c) 2014 Oleksij Rempel <linux@rempel-privat.de>
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 "libavutil/channel_layout.h"
23 #include "libavutil/intreadwrite.h"
24 
25 #include "avformat.h"
26 #include "internal.h"
27 
28 #define DSS_HEAD_OFFSET_AUTHOR        0xc
29 #define DSS_AUTHOR_SIZE               16
30 
31 #define DSS_HEAD_OFFSET_START_TIME    0x26
32 #define DSS_HEAD_OFFSET_END_TIME      0x32
33 #define DSS_TIME_SIZE                 12
34 
35 #define DSS_HEAD_OFFSET_ACODEC        0x2a4
36 #define DSS_ACODEC_DSS_SP             0x0    /* SP mode */
37 #define DSS_ACODEC_G723_1             0x2    /* LP mode */
38 
39 #define DSS_HEAD_OFFSET_COMMENT       0x31e
40 #define DSS_COMMENT_SIZE              64
41 
42 #define DSS_BLOCK_SIZE                512
43 #define DSS_AUDIO_BLOCK_HEADER_SIZE   6
44 #define DSS_FRAME_SIZE                42
45 
46 static const uint8_t frame_size[4] = { 24, 20, 4, 1 };
47 
48 typedef struct DSSDemuxContext {
49     unsigned int audio_codec;
50     int counter;
51     int swap;
52     int dss_sp_swap_byte;
53 
54     int packet_size;
55     int dss_header_size;
56 } DSSDemuxContext;
57 
dss_probe(const AVProbeData * p)58 static int dss_probe(const AVProbeData *p)
59 {
60     if (   AV_RL32(p->buf) != MKTAG(0x2, 'd', 's', 's')
61         && AV_RL32(p->buf) != MKTAG(0x3, 'd', 's', 's'))
62         return 0;
63 
64     return AVPROBE_SCORE_MAX;
65 }
66 
dss_read_metadata_date(AVFormatContext * s,unsigned int offset,const char * key)67 static int dss_read_metadata_date(AVFormatContext *s, unsigned int offset,
68                                   const char *key)
69 {
70     AVIOContext *pb = s->pb;
71     char datetime[64], string[DSS_TIME_SIZE + 1] = { 0 };
72     int y, month, d, h, minute, sec;
73     int ret;
74 
75     avio_seek(pb, offset, SEEK_SET);
76 
77     ret = avio_read(s->pb, string, DSS_TIME_SIZE);
78     if (ret < DSS_TIME_SIZE)
79         return ret < 0 ? ret : AVERROR_EOF;
80 
81     if (sscanf(string, "%2d%2d%2d%2d%2d%2d", &y, &month, &d, &h, &minute, &sec) != 6)
82         return AVERROR_INVALIDDATA;
83     /* We deal with a two-digit year here, so set the default date to 2000
84      * and hope it will never be used in the next century. */
85     snprintf(datetime, sizeof(datetime), "%.4d-%.2d-%.2dT%.2d:%.2d:%.2d",
86              y + 2000, month, d, h, minute, sec);
87     return av_dict_set(&s->metadata, key, datetime, 0);
88 }
89 
dss_read_metadata_string(AVFormatContext * s,unsigned int offset,unsigned int size,const char * key)90 static int dss_read_metadata_string(AVFormatContext *s, unsigned int offset,
91                                     unsigned int size, const char *key)
92 {
93     AVIOContext *pb = s->pb;
94     char *value;
95     int ret;
96 
97     avio_seek(pb, offset, SEEK_SET);
98 
99     value = av_mallocz(size + 1);
100     if (!value)
101         return AVERROR(ENOMEM);
102 
103     ret = avio_read(s->pb, value, size);
104     if (ret < size) {
105         av_free(value);
106         return ret < 0 ? ret : AVERROR_EOF;
107     }
108 
109     return av_dict_set(&s->metadata, key, value, AV_DICT_DONT_STRDUP_VAL);
110 }
111 
dss_read_header(AVFormatContext * s)112 static int dss_read_header(AVFormatContext *s)
113 {
114     DSSDemuxContext *ctx = s->priv_data;
115     AVIOContext *pb = s->pb;
116     AVStream *st;
117     int ret, version;
118 
119     st = avformat_new_stream(s, NULL);
120     if (!st)
121         return AVERROR(ENOMEM);
122 
123     version = avio_r8(pb);
124     ctx->dss_header_size = version * DSS_BLOCK_SIZE;
125 
126     ret = dss_read_metadata_string(s, DSS_HEAD_OFFSET_AUTHOR,
127                                    DSS_AUTHOR_SIZE, "author");
128     if (ret)
129         return ret;
130 
131     ret = dss_read_metadata_date(s, DSS_HEAD_OFFSET_END_TIME, "date");
132     if (ret)
133         return ret;
134 
135     ret = dss_read_metadata_string(s, DSS_HEAD_OFFSET_COMMENT,
136                                    DSS_COMMENT_SIZE, "comment");
137     if (ret)
138         return ret;
139 
140     avio_seek(pb, DSS_HEAD_OFFSET_ACODEC, SEEK_SET);
141     ctx->audio_codec = avio_r8(pb);
142 
143     if (ctx->audio_codec == DSS_ACODEC_DSS_SP) {
144         st->codecpar->codec_id    = AV_CODEC_ID_DSS_SP;
145         st->codecpar->sample_rate = 11025;
146         s->bit_rate = 8 * (DSS_FRAME_SIZE - 1) * st->codecpar->sample_rate
147                         * 512 / (506 * 264);
148     } else if (ctx->audio_codec == DSS_ACODEC_G723_1) {
149         st->codecpar->codec_id    = AV_CODEC_ID_G723_1;
150         st->codecpar->sample_rate = 8000;
151     } else {
152         avpriv_request_sample(s, "Support for codec %x in DSS",
153                               ctx->audio_codec);
154         return AVERROR_PATCHWELCOME;
155     }
156 
157     st->codecpar->codec_type     = AVMEDIA_TYPE_AUDIO;
158     st->codecpar->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
159 
160     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
161     st->start_time = 0;
162 
163     /* Jump over header */
164 
165     if (avio_seek(pb, ctx->dss_header_size, SEEK_SET) != ctx->dss_header_size)
166         return AVERROR(EIO);
167 
168     ctx->counter = 0;
169     ctx->swap    = 0;
170 
171     return 0;
172 }
173 
dss_skip_audio_header(AVFormatContext * s,AVPacket * pkt)174 static void dss_skip_audio_header(AVFormatContext *s, AVPacket *pkt)
175 {
176     DSSDemuxContext *ctx = s->priv_data;
177     AVIOContext *pb = s->pb;
178 
179     avio_skip(pb, DSS_AUDIO_BLOCK_HEADER_SIZE);
180     ctx->counter += DSS_BLOCK_SIZE - DSS_AUDIO_BLOCK_HEADER_SIZE;
181 }
182 
dss_sp_byte_swap(DSSDemuxContext * ctx,uint8_t * data)183 static void dss_sp_byte_swap(DSSDemuxContext *ctx, uint8_t *data)
184 {
185     int i;
186 
187     if (ctx->swap) {
188         for (i = 0; i < DSS_FRAME_SIZE - 2; i += 2)
189             data[i] = data[i + 4];
190 
191         /* Zero the padding. */
192         data[DSS_FRAME_SIZE] = 0;
193         data[1] = ctx->dss_sp_swap_byte;
194     } else {
195         ctx->dss_sp_swap_byte = data[DSS_FRAME_SIZE - 2];
196     }
197 
198     /* make sure byte 40 is always 0 */
199     data[DSS_FRAME_SIZE - 2] = 0;
200     ctx->swap             ^= 1;
201 }
202 
dss_sp_read_packet(AVFormatContext * s,AVPacket * pkt)203 static int dss_sp_read_packet(AVFormatContext *s, AVPacket *pkt)
204 {
205     DSSDemuxContext *ctx = s->priv_data;
206     int read_size, ret, offset = 0, buff_offset = 0;
207     int64_t pos = avio_tell(s->pb);
208 
209     if (ctx->counter == 0)
210         dss_skip_audio_header(s, pkt);
211 
212     if (ctx->swap) {
213         read_size   = DSS_FRAME_SIZE - 2;
214         buff_offset = 3;
215     } else
216         read_size = DSS_FRAME_SIZE;
217 
218     ret = av_new_packet(pkt, DSS_FRAME_SIZE);
219     if (ret < 0)
220         return ret;
221 
222     pkt->duration     = 264;
223     pkt->pos = pos;
224     pkt->stream_index = 0;
225 
226     if (ctx->counter < read_size) {
227         ret = avio_read(s->pb, pkt->data + buff_offset,
228                         ctx->counter);
229         if (ret < ctx->counter)
230             goto error_eof;
231 
232         offset = ctx->counter;
233         dss_skip_audio_header(s, pkt);
234     }
235     ctx->counter -= read_size;
236 
237     /* This will write one byte into pkt's padding if buff_offset == 3 */
238     ret = avio_read(s->pb, pkt->data + offset + buff_offset,
239                     read_size - offset);
240     if (ret < read_size - offset)
241         goto error_eof;
242 
243     dss_sp_byte_swap(ctx, pkt->data);
244 
245     if (ctx->dss_sp_swap_byte < 0) {
246         return AVERROR(EAGAIN);
247     }
248 
249     return 0;
250 
251 error_eof:
252     return ret < 0 ? ret : AVERROR_EOF;
253 }
254 
dss_723_1_read_packet(AVFormatContext * s,AVPacket * pkt)255 static int dss_723_1_read_packet(AVFormatContext *s, AVPacket *pkt)
256 {
257     DSSDemuxContext *ctx = s->priv_data;
258     AVStream *st = s->streams[0];
259     int size, byte, ret, offset;
260     int64_t pos = avio_tell(s->pb);
261 
262     if (ctx->counter == 0)
263         dss_skip_audio_header(s, pkt);
264 
265     /* We make one byte-step here. Don't forget to add offset. */
266     byte = avio_r8(s->pb);
267     if (byte == 0xff)
268         return AVERROR_INVALIDDATA;
269 
270     size = frame_size[byte & 3];
271 
272     ctx->packet_size = size;
273     ctx->counter--;
274 
275     ret = av_new_packet(pkt, size);
276     if (ret < 0)
277         return ret;
278     pkt->pos = pos;
279 
280     pkt->data[0]  = byte;
281     offset        = 1;
282     pkt->duration = 240;
283     s->bit_rate = 8LL * size-- * st->codecpar->sample_rate * 512 / (506 * pkt->duration);
284 
285     pkt->stream_index = 0;
286 
287     if (ctx->counter < size) {
288         ret = avio_read(s->pb, pkt->data + offset,
289                         ctx->counter);
290         if (ret < ctx->counter)
291             return ret < 0 ? ret : AVERROR_EOF;
292 
293         offset += ctx->counter;
294         size   -= ctx->counter;
295         ctx->counter = 0;
296         dss_skip_audio_header(s, pkt);
297     }
298     ctx->counter -= size;
299 
300     ret = avio_read(s->pb, pkt->data + offset, size);
301     if (ret < size)
302         return ret < 0 ? ret : AVERROR_EOF;
303 
304     return 0;
305 }
306 
dss_read_packet(AVFormatContext * s,AVPacket * pkt)307 static int dss_read_packet(AVFormatContext *s, AVPacket *pkt)
308 {
309     DSSDemuxContext *ctx = s->priv_data;
310 
311     if (ctx->audio_codec == DSS_ACODEC_DSS_SP)
312         return dss_sp_read_packet(s, pkt);
313     else
314         return dss_723_1_read_packet(s, pkt);
315 }
316 
dss_read_seek(AVFormatContext * s,int stream_index,int64_t timestamp,int flags)317 static int dss_read_seek(AVFormatContext *s, int stream_index,
318                          int64_t timestamp, int flags)
319 {
320     DSSDemuxContext *ctx = s->priv_data;
321     int64_t ret, seekto;
322     uint8_t header[DSS_AUDIO_BLOCK_HEADER_SIZE];
323     int offset;
324 
325     if (ctx->audio_codec == DSS_ACODEC_DSS_SP)
326         seekto = timestamp / 264 * 41 / 506 * 512;
327     else
328         seekto = timestamp / 240 * ctx->packet_size / 506 * 512;
329 
330     if (seekto < 0)
331         seekto = 0;
332 
333     seekto += ctx->dss_header_size;
334 
335     ret = avio_seek(s->pb, seekto, SEEK_SET);
336     if (ret < 0)
337         return ret;
338 
339     avio_read(s->pb, header, DSS_AUDIO_BLOCK_HEADER_SIZE);
340     ctx->swap = !!(header[0] & 0x80);
341     offset = 2*header[1] + 2*ctx->swap;
342     if (offset < DSS_AUDIO_BLOCK_HEADER_SIZE)
343         return AVERROR_INVALIDDATA;
344     if (offset == DSS_AUDIO_BLOCK_HEADER_SIZE) {
345         ctx->counter = 0;
346         offset = avio_skip(s->pb, -DSS_AUDIO_BLOCK_HEADER_SIZE);
347     } else {
348         ctx->counter = DSS_BLOCK_SIZE - offset;
349         offset = avio_skip(s->pb, offset - DSS_AUDIO_BLOCK_HEADER_SIZE);
350     }
351     ctx->dss_sp_swap_byte = -1;
352     return 0;
353 }
354 
355 
356 const AVInputFormat ff_dss_demuxer = {
357     .name           = "dss",
358     .long_name      = NULL_IF_CONFIG_SMALL("Digital Speech Standard (DSS)"),
359     .priv_data_size = sizeof(DSSDemuxContext),
360     .read_probe     = dss_probe,
361     .read_header    = dss_read_header,
362     .read_packet    = dss_read_packet,
363     .read_seek      = dss_read_seek,
364     .extensions     = "dss"
365 };
366