avidec.c 7.3 KB
Newer Older
Fabrice Bellard's avatar
Fabrice Bellard committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
/*
 * AVI decoder.
 * Copyright (c) 2001 Gerard Lantau.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include "avformat.h"
#include "avi.h"

//#define DEBUG

typedef struct AVIIndex {
    unsigned char tag[4];
    unsigned int flags, pos, len;
    struct AVIIndex *next;
} AVIIndex;

typedef struct {
    INT64 movi_end;
    offset_t movi_list;
    AVIIndex *first, *last;
} AVIContext;

#ifdef DEBUG
void print_tag(const char *str, unsigned int tag, int size)
{
    printf("%s: tag=%c%c%c%c size=0x%x\n",
           str, tag & 0xff,
           (tag >> 8) & 0xff,
           (tag >> 16) & 0xff,
           (tag >> 24) & 0xff,
           size);
}
#endif

int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    AVIContext *avi;
    ByteIOContext *pb = &s->pb;
    UINT32 tag, tag1;
    int codec_type, stream_index, size, frame_period, bit_rate;
54
    int i, bps;
Fabrice Bellard's avatar
Fabrice Bellard committed
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
    AVStream *st;

    avi = malloc(sizeof(AVIContext));
    if (!avi)
        return -1;
    memset(avi, 0, sizeof(AVIContext));
    s->priv_data = avi;

    /* check RIFF header */
    tag = get_le32(pb);

    if (tag != MKTAG('R', 'I', 'F', 'F'))
        return -1;
    get_le32(pb); /* file size */
    tag = get_le32(pb);
    if (tag != MKTAG('A', 'V', 'I', ' '))
        return -1;
    
    /* first list tag */
    stream_index = -1;
    codec_type = -1;
    frame_period = 0;
    for(;;) {
        if (url_feof(pb))
            goto fail;
        tag = get_le32(pb);
        size = get_le32(pb);
#ifdef DEBUG
        print_tag("tag", tag, size);
#endif

        switch(tag) {
        case MKTAG('L', 'I', 'S', 'T'):
            /* ignored, except when start of video packets */
            tag1 = get_le32(pb);
#ifdef DEBUG
            print_tag("list", tag1, 0);
#endif
            if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
                avi->movi_end = url_ftell(pb) + size - 4;
#ifdef DEBUG
                printf("movi end=%Lx\n", avi->movi_end);
#endif
                goto end_of_header;
            }
            break;
        case MKTAG('a', 'v', 'i', 'h'):
            /* avi header */
            frame_period = get_le32(pb);
            bit_rate = get_le32(pb) * 8;
            url_fskip(pb, 4 * 4);
            s->nb_streams = get_le32(pb);
            for(i=0;i<s->nb_streams;i++) {
                AVStream *st;
                st = malloc(sizeof(AVStream));
                if (!st)
                    goto fail;
                memset(st, 0, sizeof(AVStream));
                s->streams[i] = st;
            }
            url_fskip(pb, size - 7 * 4);
            break;
        case MKTAG('s', 't', 'r', 'h'):
            /* stream header */
            stream_index++;
            tag1 = get_le32(pb);
            switch(tag1) {
            case MKTAG('v', 'i', 'd', 's'):
                codec_type = CODEC_TYPE_VIDEO;
                get_le32(pb); /* codec tag */
                get_le32(pb); /* flags */
                get_le16(pb); /* priority */
                get_le16(pb); /* language */
                get_le32(pb); /* XXX: initial frame ? */
                get_le32(pb); /* scale */
                get_le32(pb); /* rate */
                url_fskip(pb, size - 7 * 4);
                break;
            case MKTAG('a', 'u', 'd', 's'):
                codec_type = CODEC_TYPE_AUDIO;
                /* nothing really useful */
                url_fskip(pb, size - 4);
                break;
            default:
                goto fail;
            }
            break;
        case MKTAG('s', 't', 'r', 'f'):
            /* stream header */
            if (stream_index >= s->nb_streams) {
                url_fskip(pb, size);
            } else {
                st = s->streams[stream_index];
                switch(codec_type) {
                case CODEC_TYPE_VIDEO:
                    get_le32(pb); /* size */
                    st->codec.width = get_le32(pb);
                    st->codec.height = get_le32(pb);
                    if (frame_period)
Fabrice Bellard's avatar
Fabrice Bellard committed
154
                        st->codec.frame_rate = (INT64_C(1000000) * FRAME_RATE_BASE) / frame_period;
Fabrice Bellard's avatar
Fabrice Bellard committed
155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177
                    else
                        st->codec.frame_rate = 25 * FRAME_RATE_BASE;
                    get_le16(pb); /* panes */
                    get_le16(pb); /* depth */
                    tag1 = get_le32(pb);
#ifdef DEBUG
                    print_tag("video", tag1, 0);
#endif
                    st->codec.codec_type = CODEC_TYPE_VIDEO;
                    st->codec.codec_tag = tag1;
                    st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
                    url_fskip(pb, size - 5 * 4);
                    break;
                case CODEC_TYPE_AUDIO:
                    tag1 = get_le16(pb);
                    st->codec.codec_type = CODEC_TYPE_AUDIO;
                    st->codec.codec_tag = tag1;
#ifdef DEBUG
                    printf("audio: 0x%x\n", tag1);
#endif
                    st->codec.channels = get_le16(pb);
                    st->codec.sample_rate = get_le32(pb);
                    st->codec.bit_rate = get_le32(pb) * 8;
178 179 180 181
                    get_le16(pb); /* block align */
                    bps = get_le16(pb);
                    st->codec.codec_id = wav_codec_get_id(tag1, bps);
                    url_fskip(pb, size - 4 * 4);
Fabrice Bellard's avatar
Fabrice Bellard committed
182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253
                    break;
                default:
                    url_fskip(pb, size);
                    break;
                }
            }
            break;
        default:
            /* skip tag */
            size += (size & 1);
            url_fskip(pb, size);
            break;
        }
    }
 end_of_header:
    /* check stream number */
    if (stream_index != s->nb_streams - 1) {
    fail:
        for(i=0;i<s->nb_streams;i++) {
            if (s->streams[i])
                free(s->streams[i]);
        }
        return -1;
    }
        
    return 0;
}

int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    AVIContext *avi = s->priv_data;
    ByteIOContext *pb = &s->pb;
    int n, d1, d2, size;
    
 find_next:
    if (url_feof(pb) || url_ftell(pb) >= avi->movi_end)
        return -1;
    d1 = get_byte(pb);
    if (d1 < '0' || d1 > '9')
        goto find_next;
    d2 = get_byte(pb);
    if (d2 < '0' || d2 > '9')
        goto find_next;
    n = (d1 - '0') * 10 + (d2 - '0');
    
    if (n < 0 || n >= s->nb_streams)
        goto find_next;
    
    d1 = get_byte(pb);
    d2 = get_byte(pb);
    if ((d1 != 'd' && d2 != 'c') &&
        (d1 != 'w' && d2 != 'b'))
        goto find_next;
    
    size = get_le32(pb);
    av_new_packet(pkt, size);
    pkt->stream_index = n;

    get_buffer(pb, pkt->data, pkt->size);
    
    if (size & 1)
        get_byte(pb);
    
    return 0;
}

int avi_read_close(AVFormatContext *s)
{
    AVIContext *avi = s->priv_data;
    free(avi);
    return 0;
}