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)
24 * for more information on the Sierra VMD file format, visit:
25 * http://www.pcisys.net/~melanson/codecs/
30 #define VMD_HEADER_SIZE 0x0330
31 #define BYTES_PER_FRAME_RECORD 16
35 offset_t frame_offset;
36 unsigned int frame_size;
39 unsigned char frame_record[BYTES_PER_FRAME_RECORD];
42 typedef struct VmdDemuxContext {
43 int video_stream_index;
44 int audio_stream_index;
46 unsigned int audio_type;
47 unsigned int audio_samplerate;
48 unsigned int audio_bits;
49 unsigned int audio_channels;
51 unsigned int frame_count;
52 vmd_frame_t *frame_table;
53 unsigned int current_frame;
56 int64_t audio_sample_counter;
57 int audio_frame_divisor;
58 int audio_block_align;
60 unsigned char vmd_header[VMD_HEADER_SIZE];
63 static int vmd_probe(AVProbeData *p)
68 /* check if the first 2 bytes of the file contain the appropriate size
69 * of a VMD header chunk */
70 if (LE_16(&p->buf[0]) != VMD_HEADER_SIZE - 2)
73 /* only return half certainty since this check is a bit sketchy */
74 return AVPROBE_SCORE_MAX / 2;
77 /* This is a support function to determine the duration, in sample
78 * frames, of a particular audio chunk, taking into account silent
80 static int vmd_calculate_audio_duration(unsigned char *audio_chunk,
81 int audio_chunk_size, int block_align)
83 unsigned char *p = audio_chunk + 16;
84 unsigned char *p_end = audio_chunk + audio_chunk_size;
85 int total_samples = 0;
86 unsigned int sound_flags;
88 if (audio_chunk_size < 16)
91 sound_flags = LE_32(p);
94 total_samples += block_align;
95 if ((sound_flags & 0x01) == 0)
100 return total_samples;
103 static int vmd_read_header(AVFormatContext *s,
104 AVFormatParameters *ap)
106 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
107 ByteIOContext *pb = &s->pb;
109 unsigned int toc_offset;
110 unsigned char *raw_frame_table;
111 int raw_frame_table_size;
112 unsigned char *current_frame_record;
113 offset_t current_offset;
115 unsigned int total_frames;
116 int64_t video_pts_inc;
117 int64_t current_video_pts = 0;
119 /* fetch the main header, including the 2 header length bytes */
120 url_fseek(pb, 0, SEEK_SET);
121 if (get_buffer(pb, vmd->vmd_header, VMD_HEADER_SIZE) != VMD_HEADER_SIZE)
124 vmd->audio_sample_counter = 0;
125 vmd->audio_frame_divisor = 1;
126 vmd->audio_block_align = 1;
128 /* start up the decoders */
129 st = av_new_stream(s, 0);
131 return AVERROR_NOMEM;
132 vmd->video_stream_index = st->index;
133 st->codec.codec_type = CODEC_TYPE_VIDEO;
134 st->codec.codec_id = CODEC_ID_VMDVIDEO;
135 st->codec.codec_tag = 0; /* no fourcc */
136 st->codec.width = LE_16(&vmd->vmd_header[12]);
137 st->codec.height = LE_16(&vmd->vmd_header[14]);
138 st->codec.extradata_size = VMD_HEADER_SIZE;
139 st->codec.extradata = av_malloc(VMD_HEADER_SIZE);
140 memcpy(st->codec.extradata, vmd->vmd_header, VMD_HEADER_SIZE);
142 /* if sample rate is 0, assume no audio */
143 vmd->sample_rate = LE_16(&vmd->vmd_header[804]);
144 if (vmd->sample_rate) {
145 st = av_new_stream(s, 0);
147 return AVERROR_NOMEM;
148 vmd->audio_stream_index = st->index;
149 st->codec.codec_type = CODEC_TYPE_AUDIO;
150 st->codec.codec_id = CODEC_ID_VMDAUDIO;
151 st->codec.codec_tag = 0; /* no codec tag */
152 st->codec.channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
153 st->codec.sample_rate = vmd->sample_rate;
154 st->codec.block_align = vmd->audio_block_align =
155 LE_16(&vmd->vmd_header[806]);
156 if (st->codec.block_align & 0x8000) {
157 st->codec.bits_per_sample = 16;
158 st->codec.block_align = -(st->codec.block_align - 0x10000);
160 st->codec.bits_per_sample = 16;
161 // st->codec.bits_per_sample = 8;
162 st->codec.bit_rate = st->codec.sample_rate *
163 st->codec.bits_per_sample * st->codec.channels;
165 /* for calculating pts */
166 vmd->audio_frame_divisor = st->codec.bits_per_sample / 8 /
169 video_pts_inc = 90000;
170 video_pts_inc *= st->codec.block_align;
171 video_pts_inc /= st->codec.sample_rate;
173 /* if no audio, assume 10 frames/second */
174 video_pts_inc = 90000 / 10;
177 /* skip over the offset table and load the table of contents; don't
178 * care about the offset table since demuxer will calculate those
180 toc_offset = LE_32(&vmd->vmd_header[812]);
181 vmd->frame_count = LE_16(&vmd->vmd_header[6]);
182 url_fseek(pb, toc_offset + vmd->frame_count * 6, SEEK_SET);
184 /* each on-disk VMD frame has an audio part and a video part; demuxer
185 * accounts them separately */
186 vmd->frame_count *= 2;
187 raw_frame_table = NULL;
188 vmd->frame_table = NULL;
189 raw_frame_table_size = vmd->frame_count * BYTES_PER_FRAME_RECORD;
190 raw_frame_table = av_malloc(raw_frame_table_size);
191 vmd->frame_table = av_malloc(vmd->frame_count * sizeof(vmd_frame_t));
192 if (!raw_frame_table || !vmd->frame_table) {
193 av_free(raw_frame_table);
194 av_free(vmd->frame_table);
195 return AVERROR_NOMEM;
197 if (get_buffer(pb, raw_frame_table, raw_frame_table_size) !=
198 raw_frame_table_size) {
199 av_free(raw_frame_table);
200 av_free(vmd->frame_table);
204 current_offset = LE_32(&vmd->vmd_header[20]);
205 current_frame_record = raw_frame_table;
206 total_frames = vmd->frame_count;
208 while (total_frames--) {
210 /* if the frame size is 0, do not count the frame and bring the
211 * total frame count down */
212 vmd->frame_table[i].frame_size = LE_32(¤t_frame_record[2]);
214 /* this logic is present so that 0-length audio chunks are not
216 if (!vmd->frame_table[i].frame_size) {
217 vmd->frame_count--; /* one less frame to count */
218 current_frame_record += BYTES_PER_FRAME_RECORD;
222 if (current_frame_record[0] == 0x02)
223 vmd->frame_table[i].stream_index = vmd->video_stream_index;
225 vmd->frame_table[i].stream_index = vmd->audio_stream_index;
226 vmd->frame_table[i].frame_offset = current_offset;
227 current_offset += vmd->frame_table[i].frame_size;
228 memcpy(vmd->frame_table[i].frame_record, current_frame_record,
229 BYTES_PER_FRAME_RECORD);
231 /* figure out the pts for this frame */
232 if (current_frame_record[0] == 0x02) {
233 vmd->frame_table[i].pts = current_video_pts;
234 current_video_pts += video_pts_inc;
235 } else if (current_frame_record[0] == 0x01) {
236 /* figure out the pts during the dispatch phase */
237 vmd->frame_table[i].pts = 0;
240 current_frame_record += BYTES_PER_FRAME_RECORD;
244 av_free(raw_frame_table);
246 /* set the pts reference at 1 pts = 1/90000 sec */
250 vmd->current_frame = 0;
255 static int vmd_read_packet(AVFormatContext *s,
258 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
259 ByteIOContext *pb = &s->pb;
263 if (vmd->current_frame >= vmd->frame_count)
266 frame = &vmd->frame_table[vmd->current_frame];
267 /* position the stream (will probably be there already) */
268 url_fseek(pb, frame->frame_offset, SEEK_SET);
270 if (av_new_packet(pkt, frame->frame_size + BYTES_PER_FRAME_RECORD))
271 return AVERROR_NOMEM;
272 memcpy(pkt->data, frame->frame_record, BYTES_PER_FRAME_RECORD);
273 ret = get_buffer(pb, pkt->data + BYTES_PER_FRAME_RECORD,
276 if (ret != frame->frame_size) {
280 pkt->stream_index = frame->stream_index;
281 if (frame->frame_record[0] == 0x02)
282 pkt->pts = frame->pts;
284 pkt->pts = vmd->audio_sample_counter;
286 pkt->pts /= vmd->sample_rate;
287 // pkt->pts /= vmd->audio_frame_divisor;
288 vmd->audio_sample_counter += vmd_calculate_audio_duration(
289 pkt->data, pkt->size, vmd->audio_block_align);
292 printf (" dispatching %s frame with %d bytes and pts %lld (%0.1f sec)\n",
293 (frame->frame_record[0] == 0x02) ? "video" : "audio",
294 frame->frame_size + BYTES_PER_FRAME_RECORD,
295 pkt->pts, (float)(pkt->pts / 90000.0));
297 vmd->current_frame++;
302 static int vmd_read_close(AVFormatContext *s)
304 VmdDemuxContext *vmd = (VmdDemuxContext *)s->priv_data;
306 av_free(vmd->frame_table);
311 static AVInputFormat vmd_iformat = {
314 sizeof(VmdDemuxContext),
323 av_register_input_format(&vmd_iformat);