2 * Sierra VMD Format Demuxer
3 * Copyright (c) 2004 The ffmpeg Project
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * Sierra VMD file demuxer
23 * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
28 #define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
29 #define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \
30 (((uint8_t*)(x))[2] << 16) | \
31 (((uint8_t*)(x))[1] << 8) | \
34 #define VMD_HEADER_SIZE 0x0330
35 #define BYTES_PER_FRAME_RECORD 16
39 offset_t frame_offset;
40 unsigned int frame_size;
43 unsigned char frame_record[BYTES_PER_FRAME_RECORD];
46 typedef struct VmdDemuxContext {
47 int video_stream_index;
48 int audio_stream_index;
50 unsigned int audio_type;
51 unsigned int audio_samplerate;
52 unsigned int audio_bits;
53 unsigned int audio_channels;
55 unsigned int frame_count;
56 vmd_frame_t *frame_table;
57 unsigned int current_frame;
59 unsigned char vmd_header[VMD_HEADER_SIZE];
62 static int vmd_probe(AVProbeData *p)
67 /* check if the first 2 bytes of the file contain the appropriate size
68 * of a VMD header chunk */
69 if (LE_16(&p->buf[0]) != VMD_HEADER_SIZE - 2)
72 /* only return half certainty since this check is a bit sketchy */
73 return AVPROBE_SCORE_MAX / 2;
76 static int vmd_read_header(AVFormatContext *s,
77 AVFormatParameters *ap)
79 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
80 ByteIOContext *pb = &s->pb;
82 unsigned int toc_offset;
83 unsigned char *raw_frame_table;
84 int raw_frame_table_size;
85 unsigned char *current_frame_record;
86 offset_t current_offset;
89 unsigned int total_frames;
90 int video_frame_count = 0;
92 /* fetch the main header, including the 2 header length bytes */
93 url_fseek(pb, 0, SEEK_SET);
94 if (get_buffer(pb, vmd->vmd_header, VMD_HEADER_SIZE) != VMD_HEADER_SIZE)
97 /* start up the decoders */
98 st = av_new_stream(s, 0);
100 return AVERROR_NOMEM;
101 vmd->video_stream_index = st->index;
102 st->codec.codec_type = CODEC_TYPE_VIDEO;
103 st->codec.codec_id = CODEC_ID_VMDVIDEO;
104 st->codec.codec_tag = 0; /* no fourcc */
105 st->codec.width = LE_16(&vmd->vmd_header[12]);
106 st->codec.height = LE_16(&vmd->vmd_header[14]);
107 st->codec.extradata_size = VMD_HEADER_SIZE;
108 st->codec.extradata = av_malloc(VMD_HEADER_SIZE);
109 memcpy(st->codec.extradata, vmd->vmd_header, VMD_HEADER_SIZE);
111 /* if sample rate is 0, assume no audio */
112 sample_rate = LE_16(&vmd->vmd_header[804]);
114 st = av_new_stream(s, 0);
116 return AVERROR_NOMEM;
117 vmd->audio_stream_index = st->index;
118 st->codec.codec_type = CODEC_TYPE_AUDIO;
119 st->codec.codec_id = CODEC_ID_VMDAUDIO;
120 st->codec.codec_tag = 0; /* no codec tag */
121 st->codec.channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
122 st->codec.sample_rate = sample_rate;
123 st->codec.bit_rate = st->codec.sample_rate *
124 st->codec.bits_per_sample * st->codec.channels;
125 st->codec.block_align = LE_16(&vmd->vmd_header[806]);
126 if (st->codec.block_align & 0x8000) {
127 st->codec.bits_per_sample = 16;
128 st->codec.block_align = -(st->codec.block_align - 0x10000);
130 st->codec.bits_per_sample = 8;
133 /* skip over the offset table and load the table of contents; don't
134 * care about the offset table since demuxer will calculate those
136 toc_offset = LE_32(&vmd->vmd_header[812]);
137 vmd->frame_count = LE_16(&vmd->vmd_header[6]);
138 url_fseek(pb, toc_offset + vmd->frame_count * 6, SEEK_SET);
140 /* each on-disk VMD frame has an audio part and a video part; demuxer
141 * accounts them separately */
142 vmd->frame_count *= 2;
143 raw_frame_table = NULL;
144 vmd->frame_table = NULL;
145 raw_frame_table_size = vmd->frame_count * BYTES_PER_FRAME_RECORD;
146 raw_frame_table = av_malloc(raw_frame_table_size);
147 vmd->frame_table = av_malloc(vmd->frame_count * sizeof(vmd_frame_t));
148 if (!raw_frame_table || !vmd->frame_table) {
149 av_free(raw_frame_table);
150 av_free(vmd->frame_table);
151 return AVERROR_NOMEM;
153 if (get_buffer(pb, raw_frame_table, raw_frame_table_size) !=
154 raw_frame_table_size) {
155 av_free(raw_frame_table);
156 av_free(vmd->frame_table);
160 current_offset = LE_32(&vmd->vmd_header[20]);
161 current_frame_record = raw_frame_table;
162 total_frames = vmd->frame_count;
164 while (total_frames--) {
166 /* if the frame size is 0, do not count the frame and bring the
167 * total frame count down */
168 vmd->frame_table[i].frame_size = LE_32(¤t_frame_record[2]);
170 /* this logic is present so that 0-length audio chunks are not
172 if (!vmd->frame_table[i].frame_size) {
173 vmd->frame_count--; /* one less frame to count */
174 current_frame_record += BYTES_PER_FRAME_RECORD;
178 if (current_frame_record[0] == 0x02)
179 vmd->frame_table[i].stream_index = vmd->video_stream_index;
181 vmd->frame_table[i].stream_index = vmd->audio_stream_index;
182 vmd->frame_table[i].frame_offset = current_offset;
183 current_offset += vmd->frame_table[i].frame_size;
184 memcpy(vmd->frame_table[i].frame_record, current_frame_record,
185 BYTES_PER_FRAME_RECORD);
187 if (current_frame_record[0] == 0x02) {
188 /* assume 15 fps for now */
189 vmd->frame_table[i].pts = video_frame_count++;
190 vmd->frame_table[i].pts *= 90000;
191 vmd->frame_table[i].pts /= 15;
194 current_frame_record += BYTES_PER_FRAME_RECORD;
198 av_free(raw_frame_table);
200 /* set the pts reference at 1 pts = 1/90000 sec */
204 vmd->current_frame = 0;
209 static int vmd_read_packet(AVFormatContext *s,
212 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
213 ByteIOContext *pb = &s->pb;
217 if (vmd->current_frame >= vmd->frame_count)
220 frame = &vmd->frame_table[vmd->current_frame];
221 /* position the stream (will probably be there already) */
222 url_fseek(pb, frame->frame_offset, SEEK_SET);
224 if (av_new_packet(pkt, frame->frame_size + BYTES_PER_FRAME_RECORD))
225 return AVERROR_NOMEM;
226 memcpy(pkt->data, frame->frame_record, BYTES_PER_FRAME_RECORD);
227 ret = get_buffer(pb, pkt->data + BYTES_PER_FRAME_RECORD,
230 if (ret != frame->frame_size)
232 pkt->stream_index = frame->stream_index;
233 pkt->pts = frame->pts;
235 vmd->current_frame++;
240 static int vmd_read_close(AVFormatContext *s)
242 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
244 av_free(vmd->frame_table);
249 static AVInputFormat vmd_iformat = {
252 sizeof(VmdDemuxContext),
261 av_register_input_format(&vmd_iformat);