rm.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

        put_be32(pb, 0);
        put_be32(pb, 0);
    }
    put_flush_packet(pb);
    return 0;
}
#endif //CONFIG_ENCODERS

/***************************************************/

static void get_str(ByteIOContext *pb, char *buf, int buf_size)
{
    int len, i;
    char *q;

    len = get_be16(pb);
    q = buf;
    for(i=0;i<len;i++) {
        if (i < buf_size - 1)
            *q++ = get_byte(pb);
    }
    *q = '\0';
}

static void get_str8(ByteIOContext *pb, char *buf, int buf_size)
{
    int len, i;
    char *q;

    len = get_byte(pb);
    q = buf;
    for(i=0;i<len;i++) {
        if (i < buf_size - 1)
            *q++ = get_byte(pb);
    }
    *q = '\0';
}

static void rm_read_audio_stream_info(AVFormatContext *s, AVStream *st, 
                                      int read_all)
{
    ByteIOContext *pb = &s->pb;
    char buf[128];
    uint32_t version;
    int i;

    /* ra type header */
    version = get_be32(pb); /* version */
    if (((version >> 16) & 0xff) == 3) {
        /* very old version */
        for(i = 0; i < 14; i++)
            get_byte(pb);
        get_str8(pb, s->title, sizeof(s->title));
        get_str8(pb, s->author, sizeof(s->author));
        get_str8(pb, s->copyright, sizeof(s->copyright));
        get_str8(pb, s->comment, sizeof(s->comment));
        get_byte(pb);
        get_str8(pb, buf, sizeof(buf));
        st->codec.sample_rate = 8000;
        st->codec.channels = 1;
        st->codec.codec_type = CODEC_TYPE_AUDIO;
        st->codec.codec_id = CODEC_ID_RA_144;
    } else {
        /* old version (4) */
        get_be32(pb); /* .ra4 */
        get_be32(pb);
        get_be16(pb);
        get_be32(pb); /* header size */
        get_be16(pb); /* add codec info */
        get_be32(pb); /* coded frame size */
        get_be32(pb); /* ??? */
        get_be32(pb); /* ??? */
        get_be32(pb); /* ??? */
        get_be16(pb); /* 1 */ 
        get_be16(pb); /* coded frame size */
        get_be32(pb);
        st->codec.sample_rate = get_be16(pb);
        get_be32(pb);
        st->codec.channels = get_be16(pb);
        get_str8(pb, buf, sizeof(buf)); /* desc */
        get_str8(pb, buf, sizeof(buf)); /* desc */
        st->codec.codec_type = CODEC_TYPE_AUDIO;
        if (!strcmp(buf, "dnet")) {
            st->codec.codec_id = CODEC_ID_AC3;
        } else {
            st->codec.codec_id = CODEC_ID_NONE;
            pstrcpy(st->codec.codec_name, sizeof(st->codec.codec_name),
                    buf);
        }
        if (read_all) {
            get_byte(pb);
            get_byte(pb);
            get_byte(pb);
            
            get_str8(pb, s->title, sizeof(s->title));
            get_str8(pb, s->author, sizeof(s->author));
            get_str8(pb, s->copyright, sizeof(s->copyright));
            get_str8(pb, s->comment, sizeof(s->comment));
        }
    }
}

static int rm_read_header_old(AVFormatContext *s, AVFormatParameters *ap)
{
    RMContext *rm = s->priv_data;
    AVStream *st;

    rm->old_format = 1;
    st = av_new_stream(s, 0);
    if (!st)
        goto fail;
    rm_read_audio_stream_info(s, st, 1);
    return 0;
 fail:
    return -1;
}

static int rm_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    RMContext *rm = s->priv_data;
    AVStream *st;
    ByteIOContext *pb = &s->pb;
    unsigned int tag, v;
    int tag_size, size, codec_data_size, i;
    int64_t codec_pos;
    unsigned int h263_hack_version, start_time, duration;
    char buf[128];
    int flags = 0;

    tag = get_le32(pb);
    if (tag == MKTAG('.', 'r', 'a', 0xfd)) {
        /* very old .ra format */
        return rm_read_header_old(s, ap);
    } else if (tag != MKTAG('.', 'R', 'M', 'F')) {
        return AVERROR_IO;
    }

    get_be32(pb); /* header size */
    get_be16(pb);
    get_be32(pb);
    get_be32(pb); /* number of headers */
    
    for(;;) {
        if (url_feof(pb))
            goto fail;
        tag = get_le32(pb);
        tag_size = get_be32(pb);
        get_be16(pb);
#if 0
        printf("tag=%c%c%c%c (%08x) size=%d\n", 
               (tag) & 0xff,
               (tag >> 8) & 0xff,
               (tag >> 16) & 0xff,
               (tag >> 24) & 0xff,
               tag,
               tag_size);
#endif
        if (tag_size < 10)
            goto fail;
        switch(tag) {
        case MKTAG('P', 'R', 'O', 'P'):
            /* file header */
            get_be32(pb); /* max bit rate */
            get_be32(pb); /* avg bit rate */
            get_be32(pb); /* max packet size */
            get_be32(pb); /* avg packet size */
            get_be32(pb); /* nb packets */
            get_be32(pb); /* duration */
            get_be32(pb); /* preroll */
            get_be32(pb); /* index offset */
            get_be32(pb); /* data offset */
            get_be16(pb); /* nb streams */
            flags = get_be16(pb); /* flags */
            break;
        case MKTAG('C', 'O', 'N', 'T'):
            get_str(pb, s->title, sizeof(s->title));
            get_str(pb, s->author, sizeof(s->author));
            get_str(pb, s->copyright, sizeof(s->copyright));
            get_str(pb, s->comment, sizeof(s->comment));
            break;
        case MKTAG('M', 'D', 'P', 'R'):
            st = av_new_stream(s, 0);
            if (!st)
                goto fail;
            st->id = get_be16(pb);
            get_be32(pb); /* max bit rate */
            st->codec.bit_rate = get_be32(pb); /* bit rate */
            get_be32(pb); /* max packet size */
            get_be32(pb); /* avg packet size */
            start_time = get_be32(pb); /* start time */
            get_be32(pb); /* preroll */
            duration = get_be32(pb); /* duration */
            st->start_time = start_time * (AV_TIME_BASE / 1000);
            st->duration = duration * (AV_TIME_BASE / 1000);
            get_str8(pb, buf, sizeof(buf)); /* desc */
            get_str8(pb, buf, sizeof(buf)); /* mimetype */
            codec_data_size = get_be32(pb);
            codec_pos = url_ftell(pb);

            v = get_be32(pb);
            if (v == MKTAG(0xfd, 'a', 'r', '.')) {
                /* ra type header */
                rm_read_audio_stream_info(s, st, 0);
            } else {
                if (get_le32(pb) != MKTAG('V', 'I', 'D', 'O')) {
                fail1:
                    av_log(&st->codec, AV_LOG_ERROR, "Unsupported video codec\n");
                    goto fail;
                }
                st->codec.codec_tag = get_le32(pb);
                if (st->codec.codec_tag != MKTAG('R', 'V', '1', '0'))
                    goto fail1;
                st->codec.width = get_be16(pb);
                st->codec.height = get_be16(pb);
                st->codec.frame_rate_base= 1;
                st->codec.frame_rate = get_be16(pb) * st->codec.frame_rate_base;
                st->codec.codec_type = CODEC_TYPE_VIDEO;
                get_be32(pb);
                get_be16(pb);
                get_be32(pb);
                get_be16(pb);
                /* modification of h263 codec version (!) */
                h263_hack_version = get_be32(pb);
                switch(h263_hack_version) {
                case 0x10000000:
                case 0x10003000:
                case 0x10003001:
                    st->codec.sub_id = h263_hack_version;
                    st->codec.codec_id = CODEC_ID_RV10;
                    break;
                default:
                    /* not handled */
                    st->codec.codec_id = CODEC_ID_NONE;
                    break;
                }
            }
            /* skip codec info */
            size = url_ftell(pb) - codec_pos;
            url_fskip(pb, codec_data_size - size);
            break;
        case MKTAG('D', 'A', 'T', 'A'):
            goto header_end;
        default:
            /* unknown tag: skip it */
            url_fskip(pb, tag_size - 10);
            break;
        }
    }
 header_end:
    rm->nb_packets = get_be32(pb); /* number of packets */
    if (!rm->nb_packets && (flags & 4))
        rm->nb_packets = 3600 * 25;
    get_be32(pb); /* next data header */
    return 0;

 fail:
    for(i=0;i<s->nb_streams;i++) {
        av_free(s->streams[i]);
    }
    return AVERROR_IO;
}

static int get_num(ByteIOContext *pb, int *len)
{
    int n, n1;

    n = get_be16(pb);
    (*len)-=2;
    if (n >= 0x4000) {
        return n - 0x4000;
    } else {
        n1 = get_be16(pb);
        (*len)-=2;
        return (n << 16) | n1;
    }
}

/* multiple of 20 bytes for ra144 (ugly) */
#define RAW_PACKET_SIZE 1000

static int rm_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    RMContext *rm = s->priv_data;
    ByteIOContext *pb = &s->pb;
    AVStream *st;
    int len, num, timestamp, i, tmp, j;
    uint8_t *ptr;
    int flags;

    if (rm->old_format) {
        /* just read raw bytes */
        len = RAW_PACKET_SIZE;
        av_new_packet(pkt, len);
        pkt->stream_index = 0;
        len = get_buffer(pb, pkt->data, len);
        if (len <= 0) {
            av_free_packet(pkt);
            return AVERROR_IO;
        }
        pkt->size = len;
        st = s->streams[0];
    } else {
    redo:
        if (rm->nb_packets == 0)
            return AVERROR_IO;
        get_be16(pb);
        len = get_be16(pb);
        if (len < 12)
            return AVERROR_IO;
        num = get_be16(pb);
        timestamp = get_be32(pb);
        get_byte(pb); /* reserved */
        flags = get_byte(pb); /* flags */
        rm->nb_packets--;
        len -= 12;
        
        st = NULL;
        for(i=0;i<s->nb_streams;i++) {
            st = s->streams[i];
            if (num == st->id)
                break;
        }
        if (i == s->nb_streams) {
            /* skip packet if unknown number */
            url_fskip(pb, len);
            goto redo;
        }
        
        if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
            int full_frame, h, pic_num;
            
            h= get_byte(pb);
            if ((h & 0xc0) == 0xc0) {
                int len2, pos;
                full_frame = 1;
                len2= get_num(pb, &len);
                pos = get_num(pb, &len);
                //printf("pos:%d\n",len);
                len -= 2;
            } else {
                int seq, frame_size, pos;
                full_frame = 0;
                seq = get_byte(pb);
                frame_size = get_num(pb, &len);
                pos = get_num(pb, &len);
                //printf("seq:%d, size:%d, pos:%d\n",seq,frame_size,pos);
                len -= 3;
            }
            /* picture number */
            pic_num= get_byte(pb);
            
            //XXX/FIXME/HACK, demuxer should be fixed to send complete frames ...
            if(st->codec.slice_offset==NULL) 
                st->codec.slice_offset= (int*)av_malloc(sizeof(int));
            st->codec.slice_count= full_frame; 
            st->codec.slice_offset[0]= 0;
        }
        
        av_new_packet(pkt, len);
        pkt->stream_index = i;
        get_buffer(pb, pkt->data, len);
    }

    /* for AC3, needs to swap bytes */
    if (st->codec.codec_id == CODEC_ID_AC3) {
        ptr = pkt->data;
        for(j=0;j<len;j+=2) {
            tmp = ptr[0];
            ptr[0] = ptr[1];
            ptr[1] = tmp;
                ptr += 2;
        }
    }
    return 0;
}

static int rm_read_close(AVFormatContext *s)
{
    return 0;
}

static int rm_probe(AVProbeData *p)
{
    /* check file header */
    if (p->buf_size <= 32)
        return 0;
    if ((p->buf[0] == '.' && p->buf[1] == 'R' &&
         p->buf[2] == 'M' && p->buf[3] == 'F' &&
         p->buf[4] == 0 && p->buf[5] == 0) ||
        (p->buf[0] == '.' && p->buf[1] == 'r' &&
         p->buf[2] == 'a' && p->buf[3] == 0xfd))
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

static AVInputFormat rm_iformat = {
    "rm",
    "rm format",
    sizeof(RMContext),
    rm_probe,
    rm_read_header,
    rm_read_packet,
    rm_read_close,
};

#ifdef CONFIG_ENCODERS
static AVOutputFormat rm_oformat = {
    "rm",
    "rm format",
    "application/vnd.rn-realmedia",
    "rm,ra",
    sizeof(RMContext),
    CODEC_ID_AC3,
    CODEC_ID_RV10,
    rm_write_header,
    rm_write_packet,
    rm_write_trailer,
};
#endif //CONFIG_ENCODERS

int rm_init(void)
{
    av_register_input_format(&rm_iformat);
#ifdef CONFIG_ENCODERS
    av_register_output_format(&rm_oformat);
#endif //CONFIG_ENCODERS
    return 0;
}