bethsoftvid.c
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1 /*
2  * Bethsoft VID format Demuxer
3  * Copyright (c) 2007 Nicholas Tung
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 
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "internal.h"
34 
35 typedef struct BVID_DemuxContext
36 {
37  int nframes;
42 
45  int video_pts;
46 
48 
50 
51 static int vid_probe(AVProbeData *p)
52 {
53  // little endian VID tag, file starts with "VID\0"
54  if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
55  return 0;
56 
57  return AVPROBE_SCORE_MAX;
58 }
59 
62 {
63  BVID_DemuxContext *vid = s->priv_data;
64  AVIOContext *pb = s->pb;
65  AVStream *stream;
66 
67  /* load main header. Contents:
68  * bytes: 'V' 'I' 'D'
69  * int16s: always_512, nframes, width, height, delay, always_14
70  */
71  avio_skip(pb, 5);
72  vid->nframes = avio_rl16(pb);
73 
74  stream = avformat_new_stream(s, NULL);
75  if (!stream)
76  return AVERROR(ENOMEM);
77  avpriv_set_pts_info(stream, 32, 1, 60); // 16 ms increments, i.e. 60 fps
80  stream->codec->width = avio_rl16(pb);
81  stream->codec->height = avio_rl16(pb);
82  stream->codec->pix_fmt = PIX_FMT_PAL8;
84  avio_rl16(pb);
85 
86  // done with video codec, set up audio codec
87  stream = avformat_new_stream(s, NULL);
88  if (!stream)
89  return AVERROR(ENOMEM);
91  stream->codec->codec_id = CODEC_ID_PCM_U8;
92  stream->codec->channels = 1;
93  stream->codec->sample_rate = 11025;
94  stream->codec->bits_per_coded_sample = 8;
95  stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_coded_sample;
96 
97  return 0;
98 }
99 
100 #define BUFFER_PADDING_SIZE 1000
102  uint8_t block_type, AVFormatContext *s, int npixels)
103 {
104  uint8_t * vidbuf_start = NULL;
105  int vidbuf_nbytes = 0;
106  int code;
107  int bytes_copied = 0;
108  int position;
109  unsigned int vidbuf_capacity;
110 
111  vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
112  if(!vidbuf_start)
113  return AVERROR(ENOMEM);
114 
115  // save the file position for the packet, include block type
116  position = avio_tell(pb) - 1;
117 
118  vidbuf_start[vidbuf_nbytes++] = block_type;
119 
120  // get the video delay (next int16), and set the presentation time
121  vid->video_pts += vid->bethsoft_global_delay + avio_rl16(pb);
122 
123  // set the y offset if it exists (decoder header data should be in data section)
124  if(block_type == VIDEO_YOFF_P_FRAME){
125  if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)
126  goto fail;
127  vidbuf_nbytes += 2;
128  }
129 
130  do{
131  vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
132  if(!vidbuf_start)
133  return AVERROR(ENOMEM);
134 
135  code = avio_r8(pb);
136  vidbuf_start[vidbuf_nbytes++] = code;
137 
138  if(code >= 0x80){ // rle sequence
139  if(block_type == VIDEO_I_FRAME)
140  vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);
141  } else if(code){ // plain sequence
142  if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code)
143  goto fail;
144  vidbuf_nbytes += code;
145  }
146  bytes_copied += code & 0x7F;
147  if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
148  // may contain a 0 byte even if read all pixels
149  if(avio_r8(pb))
150  avio_seek(pb, -1, SEEK_CUR);
151  break;
152  }
153  if(bytes_copied > npixels)
154  goto fail;
155  } while(code);
156 
157  // copy data into packet
158  if(av_new_packet(pkt, vidbuf_nbytes) < 0)
159  goto fail;
160  memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
161  av_free(vidbuf_start);
162 
163  pkt->pos = position;
164  pkt->stream_index = 0; // use the video decoder, which was initialized as the first stream
165  pkt->pts = vid->video_pts;
166 
167  vid->nframes--; // used to check if all the frames were read
168  return vidbuf_nbytes;
169 fail:
170  av_free(vidbuf_start);
171  return -1;
172 }
173 
175  AVPacket *pkt)
176 {
177  BVID_DemuxContext *vid = s->priv_data;
178  AVIOContext *pb = s->pb;
179  unsigned char block_type;
180  int audio_length;
181  int ret_value;
182 
183  if(vid->is_finished || pb->eof_reached)
184  return AVERROR(EIO);
185 
186  block_type = avio_r8(pb);
187  switch(block_type){
188  case PALETTE_BLOCK:
189  avio_seek(pb, -1, SEEK_CUR); // include block type
190  ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);
191  if(ret_value != 3 * 256 + 1){
192  av_free_packet(pkt);
193  return AVERROR(EIO);
194  }
195  pkt->stream_index = 0;
196  return ret_value;
197 
198  case FIRST_AUDIO_BLOCK:
199  avio_rl16(pb);
200  // soundblaster DAC used for sample rate, as on specification page (link above)
201  s->streams[1]->codec->sample_rate = 1000000 / (256 - avio_r8(pb));
203  case AUDIO_BLOCK:
204  audio_length = avio_rl16(pb);
205  ret_value = av_get_packet(pb, pkt, audio_length);
206  pkt->stream_index = 1;
207  return ret_value != audio_length ? AVERROR(EIO) : ret_value;
208 
209  case VIDEO_P_FRAME:
210  case VIDEO_YOFF_P_FRAME:
211  case VIDEO_I_FRAME:
212  return read_frame(vid, pb, pkt, block_type, s,
213  s->streams[0]->codec->width * s->streams[0]->codec->height);
214 
215  case EOF_BLOCK:
216  if(vid->nframes != 0)
217  av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
218  vid->is_finished = 1;
219  return AVERROR(EIO);
220  default:
221  av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
222  block_type, block_type, block_type); return -1;
223  }
224 }
225 
227  .name = "bethsoftvid",
228  .long_name = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID format"),
229  .priv_data_size = sizeof(BVID_DemuxContext),
233 };