asf.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

            put_le32(pb, codec_get_tag(codec_bmp_tags, enc->codec_id));
        }
    }
    end_header(pb, hpos);

    /* patch the header size fields */

    cur_pos = url_ftell(pb);
    header_size = cur_pos - header_offset;
    if (asf->is_streamed) {
        header_size += 8 + 30 + 50;

        url_fseek(pb, header_offset - 10 - 30, SEEK_SET);
        put_le16(pb, header_size);
        url_fseek(pb, header_offset - 2 - 30, SEEK_SET);
        put_le16(pb, header_size);

        header_size -= 8 + 30 + 50;
    }
    header_size += 24 + 6;
    url_fseek(pb, header_offset - 14, SEEK_SET);
    put_le64(pb, header_size);
    url_fseek(pb, cur_pos, SEEK_SET);

    /* movie chunk, followed by packets of packet_size */
    asf->data_offset = cur_pos;
    put_guid(pb, &data_header);
    put_le64(pb, data_chunk_size);
    put_guid(pb, &my_guid);
    put_le64(pb, asf->nb_packets); /* nb packets */
    put_byte(pb, 1); /* ??? */
    put_byte(pb, 1); /* ??? */
    return 0;
}

static int asf_write_header(AVFormatContext *s)
{
    ASFContext *asf = s->priv_data;

    av_set_pts_info(s, 32, 1, 1000); /* 32 bit pts in ms */

    asf->packet_size = PACKET_SIZE;
    asf->nb_packets = 0;

    if (asf_write_header1(s, 0, 50) < 0) {
        //av_free(asf);
        return -1;
    }

    put_flush_packet(&s->pb);

    asf->packet_nb_frames = 0;
    asf->packet_timestamp_start = -1;
    asf->packet_timestamp_end = -1;
    asf->packet_size_left = asf->packet_size - PACKET_HEADER_SIZE;
    init_put_byte(&asf->pb, asf->packet_buf, asf->packet_size, 1,
                  NULL, NULL, NULL, NULL);

    return 0;
}

static int asf_write_stream_header(AVFormatContext *s)
{
    ASFContext *asf = s->priv_data;

    asf->is_streamed = 1;

    return asf_write_header(s);
}

/* write a fixed size packet */
static int put_packet(AVFormatContext *s,
                       unsigned int timestamp, unsigned int duration,
                       int nb_frames, int padsize)
{
    ASFContext *asf = s->priv_data;
    ByteIOContext *pb = &s->pb;
    int flags;

    if (asf->is_streamed) {
        put_chunk(s, 0x4424, asf->packet_size, 0);
    }

    put_byte(pb, 0x82);
    put_le16(pb, 0);

    flags = 0x01; /* nb segments present */
    if (padsize > 0) {
        if (padsize < 256)
            flags |= 0x08;
        else
            flags |= 0x10;
    }
    put_byte(pb, flags); /* flags */
    put_byte(pb, 0x5d);
    if (flags & 0x10)
        put_le16(pb, padsize - 2);
    if (flags & 0x08)
        put_byte(pb, padsize - 1);
    put_le32(pb, timestamp);
    put_le16(pb, duration);
    put_byte(pb, nb_frames | 0x80);

    return PACKET_HEADER_SIZE + ((flags & 0x18) >> 3);
}

static void flush_packet(AVFormatContext *s)
{
    ASFContext *asf = s->priv_data;
    int hdr_size, ptr;

    hdr_size = put_packet(s, asf->packet_timestamp_start,
               asf->packet_timestamp_end - asf->packet_timestamp_start,
               asf->packet_nb_frames, asf->packet_size_left);

    /* Clear out the padding bytes */
    ptr = asf->packet_size - hdr_size - asf->packet_size_left;
    memset(asf->packet_buf + ptr, 0, asf->packet_size_left);

    put_buffer(&s->pb, asf->packet_buf, asf->packet_size - hdr_size);

    put_flush_packet(&s->pb);
    asf->nb_packets++;
    asf->packet_nb_frames = 0;
    asf->packet_timestamp_start = -1;
    asf->packet_timestamp_end = -1;
    asf->packet_size_left = asf->packet_size - PACKET_HEADER_SIZE;
    init_put_byte(&asf->pb, asf->packet_buf, asf->packet_size, 1,
                  NULL, NULL, NULL, NULL);
}

static void put_frame_header(AVFormatContext *s, ASFStream *stream, int timestamp,
                             int payload_size, int frag_offset, int frag_len)
{
    ASFContext *asf = s->priv_data;
    ByteIOContext *pb = &asf->pb;
    int val;

    val = stream->num;
    if (s->streams[val - 1]->codec.key_frame /* && frag_offset == 0 */)
        val |= 0x80;
    put_byte(pb, val);
    put_byte(pb, stream->seq);
    put_le32(pb, frag_offset); /* fragment offset */
    put_byte(pb, 0x08); /* flags */
    put_le32(pb, payload_size);
    put_le32(pb, timestamp);
    put_le16(pb, frag_len);
}


/* Output a frame. We suppose that payload_size <= PACKET_SIZE.

   It is there that you understand that the ASF format is really
   crap. They have misread the MPEG Systems spec !
 */
static void put_frame(AVFormatContext *s, ASFStream *stream, int timestamp,
                      UINT8 *buf, int payload_size)
{
    ASFContext *asf = s->priv_data;
    int frag_pos, frag_len, frag_len1;

    frag_pos = 0;
    while (frag_pos < payload_size) {
        frag_len = payload_size - frag_pos;
        frag_len1 = asf->packet_size_left - FRAME_HEADER_SIZE;
        if (frag_len1 > 0) {
            if (frag_len > frag_len1)
                frag_len = frag_len1;
            put_frame_header(s, stream, timestamp+1, payload_size, frag_pos, frag_len);
            put_buffer(&asf->pb, buf, frag_len);
            asf->packet_size_left -= (frag_len + FRAME_HEADER_SIZE);
            asf->packet_timestamp_end = timestamp;
            if (asf->packet_timestamp_start == -1)
                asf->packet_timestamp_start = timestamp;
            asf->packet_nb_frames++;
        } else {
            frag_len = 0;
        }
        frag_pos += frag_len;
        buf += frag_len;
        /* output the frame if filled */
        if (asf->packet_size_left <= FRAME_HEADER_SIZE)
            flush_packet(s);
    }
    stream->seq++;
}


static int asf_write_packet(AVFormatContext *s, int stream_index,
                            UINT8 *buf, int size, int timestamp)
{
    ASFContext *asf = s->priv_data;
    ASFStream *stream;
    INT64 duration;
    AVCodecContext *codec;

    codec = &s->streams[stream_index]->codec;
    stream = &asf->streams[stream_index];

    if (codec->codec_type == CODEC_TYPE_AUDIO) {
        duration = (codec->frame_number * codec->frame_size * INT64_C(10000000)) /
            codec->sample_rate;
    } else {
        duration = codec->frame_number *
            ((INT64_C(10000000) * FRAME_RATE_BASE) / codec->frame_rate);
    }
    if (duration > asf->duration)
        asf->duration = duration;

    put_frame(s, stream, timestamp, buf, size);
    return 0;
}

static int asf_write_trailer(AVFormatContext *s)
{
    ASFContext *asf = s->priv_data;
    INT64 file_size;

    /* flush the current packet */
    if (asf->pb.buf_ptr > asf->pb.buffer)
        flush_packet(s);

    if (asf->is_streamed) {
        put_chunk(s, 0x4524, 0, 0); /* end of stream */
    } else {
        /* rewrite an updated header */
        file_size = url_ftell(&s->pb);
        url_fseek(&s->pb, 0, SEEK_SET);
        asf_write_header1(s, file_size, file_size - asf->data_offset);
    }

    put_flush_packet(&s->pb);
    return 0;
}

/**********************************/
/* decoding */

//#define DEBUG

#ifdef DEBUG
static void print_guid(const GUID *g)
{
    int i;
    printf("0x%08x, 0x%04x, 0x%04x, {", g->v1, g->v2, g->v3);
    for(i=0;i<8;i++)
        printf(" 0x%02x,", g->v4[i]);
    printf("}\n");
}
#endif

static void get_guid(ByteIOContext *s, GUID *g)
{
    int i;

    g->v1 = get_le32(s);
    g->v2 = get_le16(s);
    g->v3 = get_le16(s);
    for(i=0;i<8;i++)
        g->v4[i] = get_byte(s);
}

#if 0
static void get_str16(ByteIOContext *pb, char *buf, int buf_size)
{
    int len, c;
    char *q;

    len = get_le16(pb);
    q = buf;
    while (len > 0) {
        c = get_le16(pb);
        if ((q - buf) < buf_size - 1)
            *q++ = c;
        len--;
    }
    *q = '\0';
}
#endif

static void get_str16_nolen(ByteIOContext *pb, int len, char *buf, int buf_size)
{
    int c;
    char *q;

    q = buf;
    while (len > 0) {
        c = get_le16(pb);
        if ((q - buf) < buf_size - 1)
            *q++ = c;
        len-=2;
    }
    *q = '\0';
}

static int asf_probe(AVProbeData *pd)
{
    GUID g;
    const unsigned char *p;
    int i;

    /* check file header */
    if (pd->buf_size <= 32)
        return 0;
    p = pd->buf;
    g.v1 = p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
    p += 4;
    g.v2 = p[0] | (p[1] << 8);
    p += 2;
    g.v3 = p[0] | (p[1] << 8);
    p += 2;
    for(i=0;i<8;i++)
        g.v4[i] = *p++;

    if (!memcmp(&g, &asf_header, sizeof(GUID)))
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    ASFContext *asf = s->priv_data;
    GUID g;
    ByteIOContext *pb = &s->pb;
    AVStream *st;
    ASFStream *asf_st;
    int size, i;
    INT64 gsize;

    av_set_pts_info(s, 32, 1, 1000); /* 32 bit pts in ms */

    get_guid(pb, &g);
    if (memcmp(&g, &asf_header, sizeof(GUID)))
        goto fail;
    get_le64(pb);
    get_le32(pb);
    get_byte(pb);
    get_byte(pb);
    memset(&asf->asfid2avid, -1, sizeof(asf->asfid2avid));
    for(;;) {
        get_guid(pb, &g);
        gsize = get_le64(pb);
#ifdef DEBUG
        printf("%08Lx: ", url_ftell(pb) - 24);
        print_guid(&g);
        printf("  size=0x%Lx\n", gsize);
#endif
        if (gsize < 24)
            goto fail;
        if (!memcmp(&g, &file_header, sizeof(GUID))) {
            get_guid(pb, &asf->hdr.guid);
	    asf->hdr.file_size		= get_le64(pb);
	    asf->hdr.create_time	= get_le64(pb);
	    asf->hdr.packets_count	= get_le64(pb);
	    asf->hdr.play_time		= get_le64(pb);
	    asf->hdr.send_time		= get_le64(pb);
	    asf->hdr.preroll		= get_le32(pb);
	    asf->hdr.ignore		= get_le32(pb);
	    asf->hdr.flags		= get_le32(pb);
	    asf->hdr.min_pktsize	= get_le32(pb);
	    asf->hdr.max_pktsize	= get_le32(pb);
	    asf->hdr.max_bitrate	= get_le32(pb);
	    asf->packet_size = asf->hdr.max_pktsize;
            asf->nb_packets = asf->hdr.packets_count;
        } else if (!memcmp(&g, &stream_header, sizeof(GUID))) {
            int type, total_size;
            unsigned int tag1;
            INT64 pos1, pos2;

            pos1 = url_ftell(pb);

            st = av_mallocz(sizeof(AVStream));
            if (!st)
                goto fail;
            s->streams[s->nb_streams] = st;
            asf_st = av_mallocz(sizeof(ASFStream));
            if (!asf_st)
                goto fail;
            st->priv_data = asf_st;
	    st->time_length = (asf->hdr.send_time - asf->hdr.preroll) / 10; // us
            get_guid(pb, &g);
            if (!memcmp(&g, &audio_stream, sizeof(GUID))) {
                type = CODEC_TYPE_AUDIO;
            } else if (!memcmp(&g, &video_stream, sizeof(GUID))) {
                type = CODEC_TYPE_VIDEO;
            } else {
                goto fail;
            }
            get_guid(pb, &g);
            total_size = get_le64(pb);
            get_le32(pb);
            get_le32(pb);
	    st->id = get_le16(pb) & 0x7f; /* stream id */
            // mapping of asf ID to AV stream ID;
            asf->asfid2avid[st->id] = s->nb_streams++;

            get_le32(pb);
	    st->codec.codec_type = type;
            st->codec.frame_rate = 15 * s->pts_den / s->pts_num; // 15 fps default
            if (type == CODEC_TYPE_AUDIO) {
                get_wav_header(pb, &st->codec, 1);
		/* We have to init the frame size at some point .... */
		pos2 = url_ftell(pb);
		if (gsize > (pos2 + 8 - pos1 + 24)) {
		    asf_st->ds_span = get_byte(pb);
		    asf_st->ds_packet_size = get_le16(pb);
		    asf_st->ds_chunk_size = get_le16(pb);
		    asf_st->ds_data_size = get_le16(pb);
		    asf_st->ds_silence_data = get_byte(pb);
		}
		//printf("Descrambling: ps:%d cs:%d ds:%d s:%d  sd:%d\n",
		//       asf_st->ds_packet_size, asf_st->ds_chunk_size,
		//       asf_st->ds_data_size, asf_st->ds_span, asf_st->ds_silence_data);
		if (asf_st->ds_span > 1) {
		    if (!asf_st->ds_chunk_size
			|| (asf_st->ds_packet_size/asf_st->ds_chunk_size <= 1))
			asf_st->ds_span = 0; // disable descrambling