1/*
2 * Bethsoft VID format Demuxer
3 * Copyright (c) 2007 Nicholas Tung
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/**
23 * @file libavformat/bethsoftvid.c
24 * @brief Bethesda Softworks VID (.vid) file demuxer
25 * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
26 * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
27 * @sa http://www.svatopluk.com/andux/docs/dfvid.html
28 */
29
30#include "libavutil/intreadwrite.h"
31#include "avformat.h"
32#include "libavcodec/bethsoftvideo.h"
33
34typedef struct BVID_DemuxContext
35{
36    int nframes;
37    /** delay value between frames, added to individual frame delay.
38     * custom units, which will be added to other custom units (~=16ms according
39     * to free, unofficial documentation) */
40    int bethsoft_global_delay;
41
42    /** video presentation time stamp.
43     * delay = 16 milliseconds * (global_delay + per_frame_delay) */
44    int video_pts;
45
46    int is_finished;
47
48} BVID_DemuxContext;
49
50static int vid_probe(AVProbeData *p)
51{
52    // little endian VID tag, file starts with "VID\0"
53    if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
54        return 0;
55
56    return AVPROBE_SCORE_MAX;
57}
58
59static int vid_read_header(AVFormatContext *s,
60                            AVFormatParameters *ap)
61{
62    BVID_DemuxContext *vid = s->priv_data;
63    ByteIOContext *pb = s->pb;
64    AVStream *stream;
65
66    /* load main header. Contents:
67    *    bytes: 'V' 'I' 'D'
68    *    int16s: always_512, nframes, width, height, delay, always_14
69    */
70    url_fseek(pb, 5, SEEK_CUR);
71    vid->nframes = get_le16(pb);
72
73    stream = av_new_stream(s, 0);
74    if (!stream)
75        return AVERROR(ENOMEM);
76    av_set_pts_info(stream, 32, 1, 60);     // 16 ms increments, i.e. 60 fps
77    stream->codec->codec_type = CODEC_TYPE_VIDEO;
78    stream->codec->codec_id = CODEC_ID_BETHSOFTVID;
79    stream->codec->width = get_le16(pb);
80    stream->codec->height = get_le16(pb);
81    stream->codec->pix_fmt = PIX_FMT_PAL8;
82    vid->bethsoft_global_delay = get_le16(pb);
83    get_le16(pb);
84
85    // done with video codec, set up audio codec
86    stream = av_new_stream(s, 0);
87    if (!stream)
88        return AVERROR(ENOMEM);
89    stream->codec->codec_type = CODEC_TYPE_AUDIO;
90    stream->codec->codec_id = CODEC_ID_PCM_U8;
91    stream->codec->channels = 1;
92    stream->codec->sample_rate = 11025;
93    stream->codec->bits_per_coded_sample = 8;
94    stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_coded_sample;
95
96    return 0;
97}
98
99#define BUFFER_PADDING_SIZE 1000
100static int read_frame(BVID_DemuxContext *vid, ByteIOContext *pb, AVPacket *pkt,
101                      uint8_t block_type, AVFormatContext *s, int npixels)
102{
103    uint8_t * vidbuf_start = NULL;
104    int vidbuf_nbytes = 0;
105    int code;
106    int bytes_copied = 0;
107    int position;
108    unsigned int vidbuf_capacity;
109
110    vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
111    if(!vidbuf_start)
112        return AVERROR(ENOMEM);
113
114    // save the file position for the packet, include block type
115    position = url_ftell(pb) - 1;
116
117    vidbuf_start[vidbuf_nbytes++] = block_type;
118
119    // get the video delay (next int16), and set the presentation time
120    vid->video_pts += vid->bethsoft_global_delay + get_le16(pb);
121
122    // set the y offset if it exists (decoder header data should be in data section)
123    if(block_type == VIDEO_YOFF_P_FRAME){
124        if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)
125            goto fail;
126        vidbuf_nbytes += 2;
127    }
128
129    do{
130        vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
131        if(!vidbuf_start)
132            return AVERROR(ENOMEM);
133
134        code = get_byte(pb);
135        vidbuf_start[vidbuf_nbytes++] = code;
136
137        if(code >= 0x80){ // rle sequence
138            if(block_type == VIDEO_I_FRAME)
139                vidbuf_start[vidbuf_nbytes++] = get_byte(pb);
140        } else if(code){ // plain sequence
141            if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], code) != code)
142                goto fail;
143            vidbuf_nbytes += code;
144        }
145        bytes_copied += code & 0x7F;
146        if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
147            // may contain a 0 byte even if read all pixels
148            if(get_byte(pb))
149                url_fseek(pb, -1, SEEK_CUR);
150            break;
151        }
152        if(bytes_copied > npixels)
153            goto fail;
154    } while(code);
155
156    // copy data into packet
157    if(av_new_packet(pkt, vidbuf_nbytes) < 0)
158        goto fail;
159    memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
160    av_free(vidbuf_start);
161
162    pkt->pos = position;
163    pkt->stream_index = 0;  // use the video decoder, which was initialized as the first stream
164    pkt->pts = vid->video_pts;
165
166    vid->nframes--;  // used to check if all the frames were read
167    return vidbuf_nbytes;
168fail:
169    av_free(vidbuf_start);
170    return -1;
171}
172
173static int vid_read_packet(AVFormatContext *s,
174                           AVPacket *pkt)
175{
176    BVID_DemuxContext *vid = s->priv_data;
177    ByteIOContext *pb = s->pb;
178    unsigned char block_type;
179    int audio_length;
180    int ret_value;
181
182    if(vid->is_finished || url_feof(pb))
183        return AVERROR(EIO);
184
185    block_type = get_byte(pb);
186    switch(block_type){
187        case PALETTE_BLOCK:
188            url_fseek(pb, -1, SEEK_CUR);     // include block type
189            ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);
190            if(ret_value != 3 * 256 + 1){
191                av_free_packet(pkt);
192                return AVERROR(EIO);
193            }
194            pkt->stream_index = 0;
195            return ret_value;
196
197        case FIRST_AUDIO_BLOCK:
198            get_le16(pb);
199            // soundblaster DAC used for sample rate, as on specification page (link above)
200            s->streams[1]->codec->sample_rate = 1000000 / (256 - get_byte(pb));
201            s->streams[1]->codec->bit_rate = s->streams[1]->codec->channels * s->streams[1]->codec->sample_rate * s->streams[1]->codec->bits_per_coded_sample;
202        case AUDIO_BLOCK:
203            audio_length = get_le16(pb);
204            ret_value = av_get_packet(pb, pkt, audio_length);
205            pkt->stream_index = 1;
206            return ret_value != audio_length ? AVERROR(EIO) : ret_value;
207
208        case VIDEO_P_FRAME:
209        case VIDEO_YOFF_P_FRAME:
210        case VIDEO_I_FRAME:
211            return read_frame(vid, pb, pkt, block_type, s,
212                              s->streams[0]->codec->width * s->streams[0]->codec->height);
213
214        case EOF_BLOCK:
215            if(vid->nframes != 0)
216                av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
217            vid->is_finished = 1;
218            return AVERROR(EIO);
219        default:
220            av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
221                   block_type, block_type, block_type); return -1;
222    }
223
224    return 0;
225}
226
227AVInputFormat bethsoftvid_demuxer = {
228    "bethsoftvid",
229    NULL_IF_CONFIG_SMALL("Bethesda Softworks VID format"),
230    sizeof(BVID_DemuxContext),
231    vid_probe,
232    vid_read_header,
233    vid_read_packet,
234};
235