Libav
lxfdec.c
Go to the documentation of this file.
1 /*
2  * LXF demuxer
3  * Copyright (c) 2010 Tomas Härdin
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <inttypes.h>
23 
24 #include "libavutil/intreadwrite.h"
25 #include "libavcodec/bytestream.h"
26 #include "avformat.h"
27 #include "internal.h"
28 
29 #define LXF_MAX_PACKET_HEADER_SIZE 256
30 #define LXF_HEADER_DATA_SIZE 120
31 #define LXF_IDENT "LEITCH\0"
32 #define LXF_IDENT_LENGTH 8
33 #define LXF_SAMPLERATE 48000
34 
35 static const AVCodecTag lxf_tags[] = {
36  { AV_CODEC_ID_MJPEG, 0 },
38  { AV_CODEC_ID_MPEG2VIDEO, 2 }, //MpMl, 4:2:0
39  { AV_CODEC_ID_MPEG2VIDEO, 3 }, //MpPl, 4:2:2
40  { AV_CODEC_ID_DVVIDEO, 4 }, //DV25
41  { AV_CODEC_ID_DVVIDEO, 5 }, //DVCPRO
42  { AV_CODEC_ID_DVVIDEO, 6 }, //DVCPRO50
43  { AV_CODEC_ID_RAWVIDEO, 7 }, //AV_PIX_FMT_ARGB, where alpha is used for chroma keying
44  { AV_CODEC_ID_RAWVIDEO, 8 }, //16-bit chroma key
45  { AV_CODEC_ID_MPEG2VIDEO, 9 }, //4:2:2 CBP ("Constrained Bytes per Gop")
46  { AV_CODEC_ID_NONE, 0 },
47 };
48 
49 typedef struct {
50  int channels;
52  uint32_t video_format, packet_type, extended_size;
54 
55 static int lxf_probe(AVProbeData *p)
56 {
57  if (!memcmp(p->buf, LXF_IDENT, LXF_IDENT_LENGTH))
58  return AVPROBE_SCORE_MAX;
59 
60  return 0;
61 }
62 
69 static int check_checksum(const uint8_t *header, int size)
70 {
71  int x;
72  uint32_t sum = 0;
73 
74  for (x = 0; x < size; x += 4)
75  sum += AV_RL32(&header[x]);
76 
77  return sum;
78 }
79 
86 static int sync(AVFormatContext *s, uint8_t *header)
87 {
89  int ret;
90 
91  if ((ret = avio_read(s->pb, buf, LXF_IDENT_LENGTH)) != LXF_IDENT_LENGTH)
92  return ret < 0 ? ret : AVERROR_EOF;
93 
94  while (memcmp(buf, LXF_IDENT, LXF_IDENT_LENGTH)) {
95  if (s->pb->eof_reached)
96  return AVERROR_EOF;
97 
98  memmove(buf, &buf[1], LXF_IDENT_LENGTH-1);
99  buf[LXF_IDENT_LENGTH-1] = avio_r8(s->pb);
100  }
101 
102  memcpy(header, LXF_IDENT, LXF_IDENT_LENGTH);
103 
104  return 0;
105 }
106 
113 {
114  LXFDemuxContext *lxf = s->priv_data;
115  AVIOContext *pb = s->pb;
116  int track_size, samples, ret;
117  uint32_t version, audio_format, header_size, channels, tmp;
118  AVStream *st;
120  const uint8_t *p = header + LXF_IDENT_LENGTH;
121 
122  //find and read the ident
123  if ((ret = sync(s, header)) < 0)
124  return ret;
125 
126  ret = avio_read(pb, header + LXF_IDENT_LENGTH, 8);
127  if (ret != 8)
128  return ret < 0 ? ret : AVERROR_EOF;
129 
130  version = bytestream_get_le32(&p);
131  header_size = bytestream_get_le32(&p);
132  if (version > 1)
133  avpriv_request_sample(s, "Unknown format version %"PRIu32"\n", version);
134 
135  if (header_size < (version ? 72 : 60) ||
136  header_size > LXF_MAX_PACKET_HEADER_SIZE ||
137  (header_size & 3)) {
138  av_log(s, AV_LOG_ERROR, "Invalid header size 0x%"PRIx32"\n", header_size);
139  return AVERROR_INVALIDDATA;
140  }
141 
142  //read the rest of the packet header
143  ret = avio_read(pb, header + (p - header), header_size - (p - header));
144  if (ret != header_size - (p - header))
145  return ret < 0 ? ret : AVERROR_EOF;
146 
147  if (check_checksum(header, header_size))
148  av_log(s, AV_LOG_ERROR, "checksum error\n");
149 
150  lxf->packet_type = bytestream_get_le32(&p);
151  p += version ? 20 : 12;
152 
153  lxf->extended_size = 0;
154  switch (lxf->packet_type) {
155  case 0:
156  //video
157  lxf->video_format = bytestream_get_le32(&p);
158  ret = bytestream_get_le32(&p);
159  //skip VBI data and metadata
160  avio_skip(pb, (int64_t)(uint32_t)AV_RL32(p + 4) +
161  (int64_t)(uint32_t)AV_RL32(p + 12));
162  break;
163  case 1:
164  //audio
165  if (s->nb_streams < 2) {
166  av_log(s, AV_LOG_INFO, "got audio packet, but no audio stream present\n");
167  break;
168  }
169 
170  if (version == 0)
171  p += 8;
172  audio_format = bytestream_get_le32(&p);
173  channels = bytestream_get_le32(&p);
174  track_size = bytestream_get_le32(&p);
175 
176  st = s->streams[1];
177 
178  //set codec based on specified audio bitdepth
179  //we only support tightly packed 16-, 20-, 24- and 32-bit PCM at the moment
180  st->codec->bits_per_coded_sample = (audio_format >> 6) & 0x3F;
181 
182  if (st->codec->bits_per_coded_sample != (audio_format & 0x3F)) {
183  av_log(s, AV_LOG_WARNING, "only tightly packed PCM currently supported\n");
184  return AVERROR_PATCHWELCOME;
185  }
186 
187  switch (st->codec->bits_per_coded_sample) {
188  case 16: st->codec->codec_id = AV_CODEC_ID_PCM_S16LE_PLANAR; break;
189  case 20: st->codec->codec_id = AV_CODEC_ID_PCM_LXF; break;
190  case 24: st->codec->codec_id = AV_CODEC_ID_PCM_S24LE_PLANAR; break;
191  case 32: st->codec->codec_id = AV_CODEC_ID_PCM_S32LE_PLANAR; break;
192  default:
194  "only 16-, 20-, 24- and 32-bit PCM currently supported\n");
195  return AVERROR_PATCHWELCOME;
196  }
197 
198  samples = track_size * 8 / st->codec->bits_per_coded_sample;
199 
200  //use audio packet size to determine video standard
201  //for NTSC we have one 8008-sample audio frame per five video frames
202  if (samples == LXF_SAMPLERATE * 5005 / 30000) {
203  avpriv_set_pts_info(s->streams[0], 64, 1001, 30000);
204  } else {
205  //assume PAL, but warn if we don't have 1920 samples
206  if (samples != LXF_SAMPLERATE / 25)
208  "video doesn't seem to be PAL or NTSC. guessing PAL\n");
209 
210  avpriv_set_pts_info(s->streams[0], 64, 1, 25);
211  }
212 
213  //TODO: warning if track mask != (1 << channels) - 1?
214  ret = av_popcount(channels) * track_size;
215 
216  break;
217  default:
218  tmp = bytestream_get_le32(&p);
219  ret = bytestream_get_le32(&p);
220  if (tmp == 1)
221  lxf->extended_size = bytestream_get_le32(&p);
222  break;
223  }
224 
225  return ret;
226 }
227 
229 {
230  LXFDemuxContext *lxf = s->priv_data;
231  AVIOContext *pb = s->pb;
232  uint8_t header_data[LXF_HEADER_DATA_SIZE];
233  int ret;
234  AVStream *st;
235  uint32_t video_params, disk_params;
236  uint16_t record_date, expiration_date;
237 
238  if ((ret = get_packet_header(s)) < 0)
239  return ret;
240 
241  if (ret != LXF_HEADER_DATA_SIZE) {
242  av_log(s, AV_LOG_ERROR, "expected %d B size header, got %d\n",
243  LXF_HEADER_DATA_SIZE, ret);
244  return AVERROR_INVALIDDATA;
245  }
246 
247  if ((ret = avio_read(pb, header_data, LXF_HEADER_DATA_SIZE)) != LXF_HEADER_DATA_SIZE)
248  return ret < 0 ? ret : AVERROR_EOF;
249 
250  if (!(st = avformat_new_stream(s, NULL)))
251  return AVERROR(ENOMEM);
252 
253  st->duration = AV_RL32(&header_data[32]);
254  video_params = AV_RL32(&header_data[40]);
255  record_date = AV_RL16(&header_data[56]);
256  expiration_date = AV_RL16(&header_data[58]);
257  disk_params = AV_RL32(&header_data[116]);
258 
260  st->codec->bit_rate = 1000000 * ((video_params >> 14) & 0xFF);
261  st->codec->codec_tag = video_params & 0xF;
262  st->codec->codec_id = ff_codec_get_id(lxf_tags, st->codec->codec_tag);
263 
264  av_log(s, AV_LOG_DEBUG, "record: %x = %i-%02i-%02i\n",
265  record_date, 1900 + (record_date & 0x7F), (record_date >> 7) & 0xF,
266  (record_date >> 11) & 0x1F);
267 
268  av_log(s, AV_LOG_DEBUG, "expire: %x = %i-%02i-%02i\n",
269  expiration_date, 1900 + (expiration_date & 0x7F), (expiration_date >> 7) & 0xF,
270  (expiration_date >> 11) & 0x1F);
271 
272  if ((video_params >> 22) & 1)
273  av_log(s, AV_LOG_WARNING, "VBI data not yet supported\n");
274 
275  if ((lxf->channels = 1 << (disk_params >> 4 & 3) + 1)) {
276  if (!(st = avformat_new_stream(s, NULL)))
277  return AVERROR(ENOMEM);
278 
281  st->codec->channels = lxf->channels;
282 
283  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
284  }
285 
286  avio_skip(s->pb, lxf->extended_size);
287 
288  return 0;
289 }
290 
292 {
293  LXFDemuxContext *lxf = s->priv_data;
294  AVIOContext *pb = s->pb;
295  uint32_t stream;
296  int ret, ret2;
297 
298  if ((ret = get_packet_header(s)) < 0)
299  return ret;
300 
301  stream = lxf->packet_type;
302 
303  if (stream > 1) {
305  "got packet with illegal stream index %"PRIu32"\n", stream);
306  return AVERROR(EAGAIN);
307  }
308 
309  if (stream == 1 && s->nb_streams < 2) {
310  av_log(s, AV_LOG_ERROR, "got audio packet without having an audio stream\n");
311  return AVERROR_INVALIDDATA;
312  }
313 
314  if ((ret2 = av_new_packet(pkt, ret)) < 0)
315  return ret2;
316 
317  if ((ret2 = avio_read(pb, pkt->data, ret)) != ret) {
318  av_free_packet(pkt);
319  return ret2 < 0 ? ret2 : AVERROR_EOF;
320  }
321 
322  pkt->stream_index = stream;
323 
324  if (!stream) {
325  //picture type (0 = closed I, 1 = open I, 2 = P, 3 = B)
326  if (((lxf->video_format >> 22) & 0x3) < 2)
327  pkt->flags |= AV_PKT_FLAG_KEY;
328 
329  pkt->dts = lxf->frame_number++;
330  }
331 
332  return ret;
333 }
334 
336  .name = "lxf",
337  .long_name = NULL_IF_CONFIG_SMALL("VR native stream (LXF)"),
338  .priv_data_size = sizeof(LXFDemuxContext),
342  .codec_tag = (const AVCodecTag* const []){lxf_tags, 0},
343 };
Bytestream IO Context.
Definition: avio.h:68
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
int size
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:243
int frame_number
current video frame
Definition: lxfdec.c:51
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
Definition: utils.c:1943
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:2829
static int sync(AVFormatContext *s, uint8_t *header)
Read input until we find the next ident.
Definition: lxfdec.c:86
#define AV_RL16
Definition: intreadwrite.h:42
static int check_checksum(const uint8_t *header, int size)
Verify the checksum of an LXF packet header.
Definition: lxfdec.c:69
AVInputFormat ff_lxf_demuxer
Definition: lxfdec.c:335
int channels
number of audio channels. zero means no audio
Definition: lxfdec.c:50
Format I/O context.
Definition: avformat.h:922
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
uint8_t
static int lxf_read_header(AVFormatContext *s)
Definition: lxfdec.c:228
#define LXF_IDENT
Definition: lxfdec.c:31
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:2521
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:990
uint8_t * data
Definition: avcodec.h:973
#define AVERROR_EOF
End of file.
Definition: error.h:51
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2507
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:452
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1019
static int lxf_probe(AVProbeData *p)
Definition: lxfdec.c:55
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:81
uint32_t packet_type
Definition: lxfdec.c:52
#define LXF_IDENT_LENGTH
Definition: lxfdec.c:32
uint32_t video_format
Definition: lxfdec.c:52
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
#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:150
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:144
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:169
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:979
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:443
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:718
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:397
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:978
int bit_rate
the average bitrate
Definition: avcodec.h:1114
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
static av_always_inline int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: avio.h:210
#define AV_RL32
Definition: intreadwrite.h:146
preferred ID for MPEG-1/2 video decoding
Definition: avcodec.h:110
#define LXF_MAX_PACKET_HEADER_SIZE
Definition: lxfdec.c:29
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:544
Stream structure.
Definition: avformat.h:699
#define AVERROR_PATCHWELCOME
Not yet implemented in Libav, patches welcome.
Definition: error.h:57
#define LXF_HEADER_DATA_SIZE
Definition: lxfdec.c:30
NULL
Definition: eval.c:55
#define AV_LOG_INFO
Standard information.
Definition: log.h:134
uint32_t extended_size
Definition: lxfdec.c:52
enum AVMediaType codec_type
Definition: avcodec.h:1058
version
Definition: ffv1enc.c:1080
enum AVCodecID codec_id
Definition: avcodec.h:1067
int sample_rate
samples per second
Definition: avcodec.h:1791
AVIOContext * pb
I/O context.
Definition: avformat.h:964
static int lxf_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: lxfdec.c:291
unsigned int codec_tag
fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
Definition: avcodec.h:1082
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:114
static int get_packet_header(AVFormatContext *s)
Read and checksum the next packet header.
Definition: lxfdec.c:112
This structure contains the data a format has to probe a file.
Definition: avformat.h:395
static const AVCodecTag lxf_tags[]
Definition: lxfdec.c:35
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:756
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:404
Main libavformat public API header.
int eof_reached
true if eof reached
Definition: avio.h:96
int channels
number of audio channels
Definition: avcodec.h:1792
void * priv_data
Format private data.
Definition: avformat.h:950
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:972
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:525
int stream_index
Definition: avcodec.h:975
This structure stores compressed data.
Definition: avcodec.h:950
#define LXF_SAMPLERATE
Definition: lxfdec.c:33