static int skeleton_header(AVFormatContext *s, int idx)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
    AVStream *st = s->streams[idx];
    uint8_t *buf = os->buf + os->pstart;
    int version_major, version_minor;
    int64_t start_num, start_den;
    uint64_t start_granule;
    int target_idx, start_time;

    strcpy(st->codec->codec_name, "skeleton");
    st->codec->codec_type = AVMEDIA_TYPE_DATA;

    if ((os->flags & OGG_FLAG_EOS) && os->psize == 0)
        return 1;

    if (os->psize < 8)
        return -1;

    if (!strncmp(buf, "fishead", 8)) {
        if (os->psize < 64)
            return -1;

        version_major = AV_RL16(buf+8);
        version_minor = AV_RL16(buf+10);

        if (version_major != 3 && version_major != 4) {
            av_log(s, AV_LOG_WARNING, "Unknown skeleton version %d.%d\n",
                   version_major, version_minor);
            return -1;
        }

        // This is the overall start time. We use it for the start time of
        // of the skeleton stream since if left unset lavf assumes 0,
        // which we don't want since skeleton is timeless
        // FIXME: the real meaning of this field is "start playback at
        // this time which can be in the middle of a packet
        start_num = AV_RL64(buf+12);
        start_den = AV_RL64(buf+20);

        if (start_den > 0 && start_num > 0) {
            int base_den;
            av_reduce(&start_time, &base_den, start_num, start_den, INT_MAX);
            avpriv_set_pts_info(st, 64, 1, base_den);
            os->lastpts =
            st->start_time = start_time;
        }
    } else if (!strncmp(buf, "fisbone", 8)) {
        if (os->psize < 52)
            return -1;

        target_idx = ogg_find_stream(ogg, AV_RL32(buf+12));
        start_granule = AV_RL64(buf+36);
        if (target_idx < 0) {
            av_log(s, AV_LOG_WARNING, "Serial number in fisbone doesn't match any stream\n");
            return 1;
        }
        os = ogg->streams + target_idx;
        if (os->start_granule != OGG_NOGRANULE_VALUE) {
            av_log(s, AV_LOG_WARNING, "Multiple fisbone for the same stream\n");
            return 1;
        }
        if (start_granule != OGG_NOGRANULE_VALUE) {
            os->start_granule = start_granule;
        }
    }

    return 1;
}

static int ipmovie_read_header(AVFormatContext *s)
{
    IPMVEContext *ipmovie = s->priv_data;
    AVIOContext *pb = s->pb;
    AVPacket pkt;
    AVStream *st;
    unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
    int chunk_type, i;
    uint8_t signature_buffer[sizeof(signature)];

    avio_read(pb, signature_buffer, sizeof(signature_buffer));
    while (memcmp(signature_buffer, signature, sizeof(signature))) {
        memmove(signature_buffer, signature_buffer + 1, sizeof(signature_buffer) - 1);
        signature_buffer[sizeof(signature_buffer) - 1] = avio_r8(pb);
        if (avio_feof(pb))
            return AVERROR_EOF;
    }
    /* initialize private context members */
    ipmovie->video_pts = ipmovie->audio_frame_count = 0;
    ipmovie->audio_chunk_offset = ipmovie->video_chunk_offset =
    ipmovie->decode_map_chunk_offset = 0;

    /* on the first read, this will position the stream at the first chunk */
    ipmovie->next_chunk_offset = avio_tell(pb) + 4;

    for (i = 0; i < 256; i++)
        ipmovie->palette[i] = 0xFFU << 24;

    /* process the first chunk which should be CHUNK_INIT_VIDEO */
    if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_VIDEO)
        return AVERROR_INVALIDDATA;

    /* peek ahead to the next chunk-- if it is an init audio chunk, process
     * it; if it is the first video chunk, this is a silent file */
    if (avio_read(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
        CHUNK_PREAMBLE_SIZE)
        return AVERROR(EIO);
    chunk_type = AV_RL16(&chunk_preamble[2]);
    avio_seek(pb, -CHUNK_PREAMBLE_SIZE, SEEK_CUR);

    if (chunk_type == CHUNK_VIDEO)
        ipmovie->audio_type = AV_CODEC_ID_NONE;  /* no audio */
    else if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_AUDIO)
        return AVERROR_INVALIDDATA;

    /* initialize the stream decoders */
    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);
    avpriv_set_pts_info(st, 63, 1, 1000000);
    ipmovie->video_stream_index = st->index;
    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codec->codec_id = AV_CODEC_ID_INTERPLAY_VIDEO;
    st->codec->codec_tag = 0;  /* no fourcc */
    st->codec->width = ipmovie->video_width;
    st->codec->height = ipmovie->video_height;
    st->codec->bits_per_coded_sample = ipmovie->video_bpp;

    if (ipmovie->audio_type) {
        st = avformat_new_stream(s, NULL);
        if (!st)
            return AVERROR(ENOMEM);
        avpriv_set_pts_info(st, 32, 1, ipmovie->audio_sample_rate);
        ipmovie->audio_stream_index = st->index;
        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        st->codec->codec_id = ipmovie->audio_type;
        st->codec->codec_tag = 0;  /* no tag */
        st->codec->channels = ipmovie->audio_channels;
        st->codec->channel_layout = st->codec->channels == 1 ? AV_CH_LAYOUT_MONO :
                                                               AV_CH_LAYOUT_STEREO;
        st->codec->sample_rate = ipmovie->audio_sample_rate;
        st->codec->bits_per_coded_sample = ipmovie->audio_bits;
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
            st->codec->bits_per_coded_sample;
        if (st->codec->codec_id == AV_CODEC_ID_INTERPLAY_DPCM)
            st->codec->bit_rate /= 2;
        st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
    }

    return 0;
}

/** Read incoming MMST media, header or command packet. */
static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
{
    int read_result;
    MMSSCPacketType packet_type= -1;
    MMSContext *mms = &mmst->mms;
    for(;;) {
        read_result = url_read_complete(mms->mms_hd, mms->in_buffer, 8);
        if (read_result != 8) {
            if(read_result < 0) {
                av_log(NULL, AV_LOG_ERROR,
                       "Error reading packet header: %d (%s)\n",
                       read_result, strerror(read_result));
                packet_type = SC_PKT_CANCEL;
            } else {
                av_log(NULL, AV_LOG_ERROR,
                       "The server closed the connection\n");
                packet_type = SC_PKT_NO_DATA;
            }
            return packet_type;
        }

        // handle command packet.
        if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {
            int length_remaining, hr;

            mmst->incoming_flags= mms->in_buffer[3];
            read_result= url_read_complete(mms->mms_hd, mms->in_buffer+8, 4);
            if(read_result != 4) {
                av_log(NULL, AV_LOG_ERROR,
                       "Reading command packet length failed: %d (%s)\n",
                       read_result,
                       read_result < 0 ? strerror(read_result) :
                           "The server closed the connection");
                return read_result < 0 ? read_result : AVERROR_IO;
            }

            length_remaining= AV_RL32(mms->in_buffer+8) + 4;
            dprintf(NULL, "Length remaining is %d\n", length_remaining);
            // read the rest of the packet.
            if (length_remaining < 0
                || length_remaining > sizeof(mms->in_buffer) - 12) {
                av_log(NULL, AV_LOG_ERROR,
                       "Incoming packet length %d exceeds bufsize %zu\n",
                       length_remaining, sizeof(mms->in_buffer) - 12);
                return AVERROR_INVALIDDATA;
            }
            read_result = url_read_complete(mms->mms_hd, mms->in_buffer + 12,
                                            length_remaining) ;
            if (read_result != length_remaining) {
                av_log(NULL, AV_LOG_ERROR,
                       "Reading pkt data (length=%d) failed: %d (%s)\n",
                       length_remaining, read_result,
                       read_result < 0 ? strerror(read_result) :
                           "The server closed the connection");
                return read_result < 0 ? read_result : AVERROR_IO;
            }
            packet_type= AV_RL16(mms->in_buffer+36);
            hr = AV_RL32(mms->in_buffer + 40);
            if (hr) {
                av_log(NULL, AV_LOG_ERROR,
                       "Server sent an error status code: 0x%08x\n", hr);
                return AVERROR_UNKNOWN;
            }
        } else {
            int length_remaining;
            int packet_id_type;
            int tmp;

            // note we cache the first 8 bytes,
            // then fill up the buffer with the others
            tmp                       = AV_RL16(mms->in_buffer + 6);
            length_remaining          = (tmp - 8) & 0xffff;
            mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);
            packet_id_type            = mms->in_buffer[4];
            mmst->incoming_flags      = mms->in_buffer[5];

            if (length_remaining < 0
                || length_remaining > sizeof(mms->in_buffer) - 8) {
                av_log(NULL, AV_LOG_ERROR,
                       "Data length %d is invalid or too large (max=%zu)\n",
                       length_remaining, sizeof(mms->in_buffer));
                return AVERROR_INVALIDDATA;
            }
            mms->remaining_in_len    = length_remaining;
            mms->read_in_ptr         = mms->in_buffer;
            read_result= url_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
            if(read_result != length_remaining) {
                av_log(NULL, AV_LOG_ERROR,
                       "Failed to read packet data of size %d: %d (%s)\n",
                       length_remaining, read_result,
                       read_result < 0 ? strerror(read_result) :
                           "The server closed the connection");
                return read_result < 0 ? read_result : AVERROR_IO;
            }

            // if we successfully read everything.
            if(packet_id_type == mmst->header_packet_id) {
                packet_type = SC_PKT_ASF_HEADER;
                // Store the asf header
//.........这里部分代码省略.........

static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                        AVPacket *avpkt)
{
    AVFrame *frame = data;
    const uint8_t *buf = avpkt->data;
    const uint8_t *buf_end = buf + avpkt->size;
    KgvContext * const c = avctx->priv_data;
    int offsets[8];
    uint8_t *out, *prev;
    int outcnt = 0, maxcnt;
    int w, h, i, res;

    if (avpkt->size < 2)
        return AVERROR_INVALIDDATA;

    w = (buf[0] + 1) * 8;
    h = (buf[1] + 1) * 8;
    buf += 2;

    if (w != avctx->width || h != avctx->height) {
        av_freep(&c->frame_buffer);
        av_freep(&c->last_frame_buffer);
        if ((res = ff_set_dimensions(avctx, w, h)) < 0)
            return res;
    }

    if (!c->frame_buffer) {
        c->frame_buffer      = av_mallocz(avctx->width * avctx->height * 2);
        c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
        if (!c->frame_buffer || !c->last_frame_buffer) {
            decode_flush(avctx);
            return AVERROR(ENOMEM);
        }
    }

    maxcnt = w * h;

    if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
        return res;
    out  = (uint8_t*)c->frame_buffer;
    prev = (uint8_t*)c->last_frame_buffer;

    for (i = 0; i < 8; i++)
        offsets[i] = -1;

    while (outcnt < maxcnt && buf_end - 2 >= buf) {
        int code = AV_RL16(buf);
        buf += 2;

        if (!(code & 0x8000)) {
            AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
            outcnt++;
        } else {
            int count;

            if ((code & 0x6000) == 0x6000) {
                // copy from previous frame
                int oidx = (code >> 10) & 7;
                int start;

                count = (code & 0x3FF) + 3;

                if (offsets[oidx] < 0) {
                    if (buf_end - 3 < buf)
                        break;
                    offsets[oidx] = AV_RL24(buf);
                    buf += 3;
                }

                start = (outcnt + offsets[oidx]) % maxcnt;

                if (maxcnt - start < count || maxcnt - outcnt < count)
                    break;

                if (!prev) {
                    av_log(avctx, AV_LOG_ERROR,
                           "Frame reference does not exist\n");
                    break;
                }

                memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
            } else {
                // copy from earlier in this frame
                int offset = (code & 0x1FFF) + 1;

                if (!(code & 0x6000)) {
                    count = 2;
                } else if ((code & 0x6000) == 0x2000) {
                    count = 3;
                } else {
                    if (buf_end - 1 < buf)
                        break;
                    count = 4 + *buf++;
                }

                if (outcnt < offset || maxcnt - outcnt < count)
                    break;

                av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
            }
//.........这里部分代码省略.........

/* Returns the number of bytes consumed from the bytestream. Returns -1 if
 * there was an error while decoding the header */
static int truemotion1_decode_header(TrueMotion1Context *s)
{
    int i;
    int width_shift = 0;
    int new_pix_fmt;
    struct frame_header header;
    uint8_t header_buffer[128] = { 0 };  /* logical maximum size of the header */
    const uint8_t *sel_vector_table;

    header.header_size = ((s->buf[0] >> 5) | (s->buf[0] << 3)) & 0x7f;
    if (s->buf[0] < 0x10 || header.header_size >= s->size)
    {
        av_log(s->avctx, AV_LOG_ERROR, "invalid header size (%d)\n", s->buf[0]);
        return -1;
    }

    /* unscramble the header bytes with a XOR operation */
    for (i = 1; i < header.header_size; i++)
        header_buffer[i - 1] = s->buf[i] ^ s->buf[i + 1];

    header.compression = header_buffer[0];
    header.deltaset = header_buffer[1];
    header.vectable = header_buffer[2];
    header.ysize = AV_RL16(&header_buffer[3]);
    header.xsize = AV_RL16(&header_buffer[5]);
    header.checksum = AV_RL16(&header_buffer[7]);
    header.version = header_buffer[9];
    header.header_type = header_buffer[10];
    header.flags = header_buffer[11];
    header.control = header_buffer[12];

    /* Version 2 */
    if (header.version >= 2)
    {
        if (header.header_type > 3)
        {
            av_log(s->avctx, AV_LOG_ERROR, "invalid header type (%d)\n", header.header_type);
            return -1;
        } else if ((header.header_type == 2) || (header.header_type == 3)) {
            s->flags = header.flags;
            if (!(s->flags & FLAG_INTERFRAME))
                s->flags |= FLAG_KEYFRAME;
        } else
            s->flags = FLAG_KEYFRAME;
    } else /* Version 1 */
        s->flags = FLAG_KEYFRAME;

    if (s->flags & FLAG_SPRITE) {
        av_log_ask_for_sample(s->avctx, "SPRITE frame found.\n");
        /* FIXME header.width, height, xoffset and yoffset aren't initialized */
#if 0
        s->w = header.width;
        s->h = header.height;
        s->x = header.xoffset;
        s->y = header.yoffset;
#else
        return -1;
#endif
    } else {
        s->w = header.xsize;
        s->h = header.ysize;
        if (header.header_type < 2) {
            if ((s->w < 213) && (s->h >= 176))
            {
                s->flags |= FLAG_INTERPOLATED;
                av_log_ask_for_sample(s->avctx, "INTERPOLATION selected.\n");
            }
        }
    }

    if (header.compression >= 17) {
        av_log(s->avctx, AV_LOG_ERROR, "invalid compression type (%d)\n", header.compression);
        return -1;
    }

    if ((header.deltaset != s->last_deltaset) ||
        (header.vectable != s->last_vectable))
        select_delta_tables(s, header.deltaset);

    if ((header.compression & 1) && header.header_type)
        sel_vector_table = pc_tbl2;
    else {
        if (header.vectable > 0 && header.vectable < 4)
            sel_vector_table = tables[header.vectable - 1];
        else {
            av_log(s->avctx, AV_LOG_ERROR, "invalid vector table id (%d)\n", header.vectable);
            return -1;
        }
    }

    if (compression_types[header.compression].algorithm == ALGO_RGB24H) {
        new_pix_fmt = PIX_FMT_RGB32;
        width_shift = 1;
    } else
        new_pix_fmt = PIX_FMT_RGB555; // RGB565 is supported as well

    s->w >>= width_shift;
    if (av_image_check_size(s->w, s->h, 0, s->avctx) < 0)
//.........这里部分代码省略.........

static int str_probe(AVProbeData *p)
{
    uint8_t *sector= p->buf;
    uint8_t *end= sector + p->buf_size;
    int aud=0, vid=0;

    if (p->buf_size < RAW_CD_SECTOR_SIZE)
        return 0;

    if ((AV_RL32(&p->buf[0]) == RIFF_TAG) &&
        (AV_RL32(&p->buf[8]) == CDXA_TAG)) {

        /* RIFF header seen; skip 0x2C bytes */
        sector += RIFF_HEADER_SIZE;
    }

    while (end - sector >= RAW_CD_SECTOR_SIZE) {
        /* look for CD sync header (00, 0xFF x 10, 00) */
        if (memcmp(sector,sync_header,sizeof(sync_header)))
            return 0;

        if (sector[0x11] >= 32)
            return 0;

        switch (sector[0x12] & CDXA_TYPE_MASK) {
        case CDXA_TYPE_DATA:
        case CDXA_TYPE_VIDEO: {
                int current_sector = AV_RL16(&sector[0x1C]);
                int sector_count   = AV_RL16(&sector[0x1E]);
                int frame_size = AV_RL32(&sector[0x24]);

                if(!(   frame_size>=0
                     && current_sector < sector_count
                     && sector_count*VIDEO_DATA_CHUNK_SIZE >=frame_size)){
                    return 0;
                }

                /*st->codec->width      = AV_RL16(&sector[0x28]);
                st->codec->height     = AV_RL16(&sector[0x2A]);*/

//                 if (current_sector == sector_count-1) {
                    vid++;
//                 }

            }
            break;
        case CDXA_TYPE_AUDIO:
            if(sector[0x13]&0x2A)
                return 0;
            aud++;
            break;
        default:
            if(sector[0x12] & CDXA_TYPE_MASK)
                return 0;
        }
        sector += RAW_CD_SECTOR_SIZE;
    }
    /* MPEG files (like those ripped from VCDs) can also look like this;
     * only return half certainty */
    if(vid+aud > 3)  return 50;
    else if(vid+aud) return 1;
    else             return 0;
}

static int get_ext_stream_properties(char *buf, int buf_len, int stream_num, struct asf_priv* asf, int is_video)
{
  int pos=0;
  uint8_t *buffer = &buf[0];
  uint64_t avg_ft;
  unsigned bitrate;

  while ((pos = find_asf_guid(buf, asf_ext_stream_header, pos, buf_len)) >= 0) {
    int this_stream_num, stnamect, payct, i;
    int buf_max_index=pos+50;
    if (buf_max_index > buf_len) return 0;
    buffer = &buf[pos];

    // the following info is available
    // some of it may be useful but we're skipping it for now
    // starttime(8 bytes), endtime(8),
    // leak-datarate(4), bucket-datasize(4), init-bucket-fullness(4),
    // alt-leak-datarate(4), alt-bucket-datasize(4), alt-init-bucket-fullness(4),
    // max-object-size(4),
    // flags(4) (reliable,seekable,no_cleanpoints?,resend-live-cleanpoints, rest of bits reserved)

    buffer += 8+8;
    bitrate = AV_RL32(buffer);
    buffer += 8*4;
    this_stream_num=AV_RL16(buffer);buffer+=2;

    if (this_stream_num == stream_num) {
      buf_max_index+=14;
      if (buf_max_index > buf_len) return 0;
      buffer+=2; //skip stream-language-id-index
      avg_ft = AV_RL64(buffer); // provided in 100ns units
      buffer+=8;
      asf->bps = bitrate / 8;

      // after this are values for stream-name-count and
      // payload-extension-system-count
      // followed by associated info for each
      stnamect = AV_RL16(buffer);buffer+=2;
      payct = AV_RL16(buffer);buffer+=2;

      // need to read stream names if present in order
      // to get lengths - values are ignored for now
      for (i=0; i<stnamect; i++) {
        int stream_name_len;
        buf_max_index+=4;
        if (buf_max_index > buf_len) return 0;
        buffer+=2; //language_id_index
        stream_name_len = AV_RL16(buffer);buffer+=2;
        buffer+=stream_name_len; //stream_name
        buf_max_index+=stream_name_len;
        if (buf_max_index > buf_len) return 0;
      }

      if (is_video) {
        asf->vid_repdata_count = payct;
        asf->vid_repdata_sizes = malloc(payct*sizeof(int));
      } else {
        asf->aud_repdata_count = payct;
        asf->aud_repdata_sizes = malloc(payct*sizeof(int));
      }

      for (i=0; i<payct; i++) {
        int payload_len;
        buf_max_index+=22;
        if (buf_max_index > buf_len) return 0;
        // Each payload extension definition starts with a GUID.
        // In dvr-ms files one of these indicates the presence an
        // extension that contains pts values and this is always present
        // in the video and audio streams.
        // Another GUID indicates the presence of an extension
        // that contains useful video frame demuxing information.
        // Note that the extension data in each packet does not contain
        // these GUIDs and that this header section defines the order the data
        // will appear in.
        if (memcmp(buffer, asf_dvr_ms_timing_rep_data, 16) == 0) {
          if (is_video)
            asf->vid_ext_timing_index = i;
          else
            asf->aud_ext_timing_index = i;
        } else if (is_video && memcmp(buffer, asf_dvr_ms_vid_frame_rep_data, 16) == 0)
          asf->vid_ext_frame_index = i;
        buffer+=16;

        payload_len = AV_RL16(buffer);buffer+=2;

        if (is_video)
          asf->vid_repdata_sizes[i] = payload_len;
        else
          asf->aud_repdata_sizes[i] = payload_len;
        buffer+=4;//sys_len
      }

      return 1;
    }
  }
  return 1;
}

static int wsvqa_read_header(AVFormatContext *s,
                             AVFormatParameters *ap)
{
    WsVqaDemuxContext *wsvqa = s->priv_data;
    ByteIOContext *pb = s->pb;
    AVStream *st;
    unsigned char *header;
    unsigned char scratch[VQA_PREAMBLE_SIZE];
    unsigned int chunk_tag;
    unsigned int chunk_size;

    /* initialize the video decoder stream */
    st = av_new_stream(s, 0);
    if (!st)
        return AVERROR(ENOMEM);
    av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
    wsvqa->video_stream_index = st->index;
    st->codec->codec_type = CODEC_TYPE_VIDEO;
    st->codec->codec_id = CODEC_ID_WS_VQA;
    st->codec->codec_tag = 0;  /* no fourcc */

    /* skip to the start of the VQA header */
    url_fseek(pb, 20, SEEK_SET);

    /* the VQA header needs to go to the decoder */
    st->codec->extradata_size = VQA_HEADER_SIZE;
    st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
    header = (unsigned char *)st->codec->extradata;
    if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
        VQA_HEADER_SIZE) {
        av_free(st->codec->extradata);
        return AVERROR(EIO);
    }
    st->codec->width = AV_RL16(&header[6]);
    st->codec->height = AV_RL16(&header[8]);

    /* initialize the audio decoder stream for VQA v1 or nonzero samplerate */
    if (AV_RL16(&header[24]) || (AV_RL16(&header[0]) == 1 && AV_RL16(&header[2]) == 1)) {
        st = av_new_stream(s, 0);
        if (!st)
            return AVERROR(ENOMEM);
        av_set_pts_info(st, 33, 1, VQA_FRAMERATE);
        st->codec->codec_type = CODEC_TYPE_AUDIO;
        if (AV_RL16(&header[0]) == 1)
            st->codec->codec_id = CODEC_ID_WESTWOOD_SND1;
        else
            st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS;
        st->codec->codec_tag = 0;  /* no tag */
        st->codec->sample_rate = AV_RL16(&header[24]);
        if (!st->codec->sample_rate)
            st->codec->sample_rate = 22050;
        st->codec->channels = header[26];
        if (!st->codec->channels)
            st->codec->channels = 1;
        st->codec->bits_per_coded_sample = 16;
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
            st->codec->bits_per_coded_sample / 4;
        st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;

        wsvqa->audio_stream_index = st->index;
        wsvqa->audio_samplerate = st->codec->sample_rate;
        wsvqa->audio_channels = st->codec->channels;
        wsvqa->audio_frame_counter = 0;
    }

    /* there are 0 or more chunks before the FINF chunk; iterate until
     * FINF has been skipped and the file will be ready to be demuxed */
    do {
        if (get_buffer(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE) {
            av_free(st->codec->extradata);
            return AVERROR(EIO);
        }
        chunk_tag = AV_RB32(&scratch[0]);
        chunk_size = AV_RB32(&scratch[4]);

        /* catch any unknown header tags, for curiousity */
        switch (chunk_tag) {
        case CINF_TAG:
        case CINH_TAG:
        case CIND_TAG:
        case PINF_TAG:
        case PINH_TAG:
        case PIND_TAG:
        case FINF_TAG:
        case CMDS_TAG:
            break;

        default:
            av_log (s, AV_LOG_ERROR, " note: unknown chunk seen (%c%c%c%c)\n",
                scratch[0], scratch[1],
                scratch[2], scratch[3]);
            break;
        }

        url_fseek(pb, chunk_size, SEEK_CUR);
    } while (chunk_tag != FINF_TAG);

    wsvqa->video_pts = wsvqa->audio_frame_counter = 0;

    return 0;
//.........这里部分代码省略.........

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *data_size,
                        AVPacket *avpkt)
{
    PicContext *s = avctx->priv_data;
    int buf_size = avpkt->size;
    const uint8_t *buf = avpkt->data;
    const uint8_t *buf_end = avpkt->data + buf_size;
    uint32_t *palette;
    int bits_per_plane, bpp, etype, esize, npal;
    int i, x, y, plane;

    if (buf_size < 11)
        return AVERROR_INVALIDDATA;

    if (bytestream_get_le16(&buf) != 0x1234)
        return AVERROR_INVALIDDATA;
    s->width  = bytestream_get_le16(&buf);
    s->height = bytestream_get_le16(&buf);
    buf += 4;
    bits_per_plane    = *buf & 0xF;
    s->nb_planes      = (*buf++ >> 4) + 1;
    bpp               = s->nb_planes ? bits_per_plane*s->nb_planes : bits_per_plane;
    if (bits_per_plane > 8 || bpp < 1 || bpp > 32) {
        av_log_ask_for_sample(s, "unsupported bit depth\n");
        return AVERROR_INVALIDDATA;
    }

    if (*buf == 0xFF) {
        buf += 2;
        etype  = bytestream_get_le16(&buf);
        esize  = bytestream_get_le16(&buf);
        if (buf_end - buf < esize)
            return AVERROR_INVALIDDATA;
    } else {
        etype = -1;
        esize = 0;
    }

    avctx->pix_fmt = PIX_FMT_PAL8;

    if (s->width != avctx->width && s->height != avctx->height) {
        if (av_image_check_size(s->width, s->height, 0, avctx) < 0)
            return -1;
        avcodec_set_dimensions(avctx, s->width, s->height);
        if (s->frame.data[0])
            avctx->release_buffer(avctx, &s->frame);
    }

    if (avctx->get_buffer(avctx, &s->frame) < 0){
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }
    memset(s->frame.data[0], 0, s->height * s->frame.linesize[0]);
    s->frame.pict_type           = AV_PICTURE_TYPE_I;
    s->frame.palette_has_changed = 1;

    palette = (uint32_t*)s->frame.data[1];
    if (etype == 1 && esize > 1 && *buf < 6) {
        int idx = *buf;
        npal = 4;
        for (i = 0; i < npal; i++)
            palette[i] = ff_cga_palette[ cga_mode45_index[idx][i] ];
    } else if (etype == 2) {
        npal = FFMIN(esize, 16);
        for (i = 0; i < npal; i++)
            palette[i] = ff_cga_palette[ FFMIN(buf[i], 16)];
    } else if (etype == 3) {
        npal = FFMIN(esize, 16);
        for (i = 0; i < npal; i++)
            palette[i] = ff_ega_palette[ FFMIN(buf[i], 63)];
    } else if (etype == 4 || etype == 5) {
        npal = FFMIN(esize / 3, 256);
        for (i = 0; i < npal; i++)
            palette[i] = AV_RB24(buf + i*3) << 2;
    } else {
        if (bpp == 1) {
            npal = 2;
            palette[0] = 0x000000;
            palette[1] = 0xFFFFFF;
        } else if (bpp == 2) {
            npal = 4;
            for (i = 0; i < npal; i++)
                palette[i] = ff_cga_palette[ cga_mode45_index[0][i] ];
        } else {
            npal = 16;
            memcpy(palette, ff_cga_palette, npal * 4);
        }
    }
    // fill remaining palette entries
    memset(palette + npal, 0, AVPALETTE_SIZE - npal * 4);
    buf += esize;


    x = 0;
    y = s->height - 1;
    plane = 0;
    if (bytestream_get_le16(&buf)) {
        while (buf_end - buf >= 6) {
            const uint8_t *buf_pend = buf + FFMIN(AV_RL16(buf), buf_end - buf);
//.........这里部分代码省略.........

static int ws_snd_decode_frame(AVCodecContext *avctx,
                void *data, int *data_size,
                AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
//    WSSNDContext *c = avctx->priv_data;

    int in_size, out_size;
    int sample = 0;
    int i;
    short *samples = data;

    if (!buf_size)
        return 0;

    out_size = AV_RL16(&buf[0]);
    *data_size = out_size * 2;
    in_size = AV_RL16(&buf[2]);
    buf += 4;

    if (out_size > *data_size) {
        av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");
        return -1;
    }
    if (in_size > buf_size) {
        av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
        return -1;
    }
    if (in_size == out_size) {
        for (i = 0; i < out_size; i++)
            *samples++ = (*buf++ - 0x80) << 8;
        return buf_size;
    }

    while (out_size > 0) {
        int code;
        uint8_t count;
        code = (*buf) >> 6;
        count = (*buf) & 0x3F;
        buf++;
        switch(code) {
        case 0: /* ADPCM 2-bit */
            for (count++; count > 0; count--) {
                code = *buf++;
                sample += ws_adpcm_2bit[code & 0x3];
                CLIP8(sample);
                *samples++ = sample << 8;
                sample += ws_adpcm_2bit[(code >> 2) & 0x3];
                CLIP8(sample);
                *samples++ = sample << 8;
                sample += ws_adpcm_2bit[(code >> 4) & 0x3];
                CLIP8(sample);
                *samples++ = sample << 8;
                sample += ws_adpcm_2bit[(code >> 6) & 0x3];
                CLIP8(sample);
                *samples++ = sample << 8;
                out_size -= 4;
            }
            break;
        case 1: /* ADPCM 4-bit */
            for (count++; count > 0; count--) {
                code = *buf++;
                sample += ws_adpcm_4bit[code & 0xF];
                CLIP8(sample);
                *samples++ = sample << 8;
                sample += ws_adpcm_4bit[code >> 4];
                CLIP8(sample);
                *samples++ = sample << 8;
                out_size -= 2;
            }
            break;
        case 2: /* no compression */
            if (count & 0x20) { /* big delta */
                int8_t t;
                t = count;
                t <<= 3;
                sample += t >> 3;
                *samples++ = sample << 8;
                out_size--;
            } else { /* copy */
                for (count++; count > 0; count--) {
                    *samples++ = (*buf++ - 0x80) << 8;
                    out_size--;
                }
                sample = buf[-1] - 0x80;
            }
            break;
        default: /* run */
            for(count++; count > 0; count--) {
                *samples++ = sample << 8;
                out_size--;
            }
        }

    vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
    vst->codec->codec_id = vmd->is_indeo3 ? CODEC_ID_INDEO3 : CODEC_ID_VMDVIDEO;
    vst->codec->codec_tag = 0;  /* no fourcc */
    vst->codec->width = AV_RL16(&vmd->vmd_header[12]);
    vst->codec->height = AV_RL16(&vmd->vmd_header[14]);
    if(vmd->is_indeo3 && vst->codec->width > 320)
    {
        vst->codec->width >>= 1;
        vst->codec->height >>= 1;
    }
    vst->codec->extradata_size = VMD_HEADER_SIZE;
    vst->codec->extradata = av_mallocz(VMD_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
    memcpy(vst->codec->extradata, vmd->vmd_header, VMD_HEADER_SIZE);

    /* if sample rate is 0, assume no audio */
    vmd->sample_rate = AV_RL16(&vmd->vmd_header[804]);
    if (vmd->sample_rate)
    {
        st = av_new_stream(s, 0);
        if (!st)
            return AVERROR(ENOMEM);
        vmd->audio_stream_index = st->index;
        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        st->codec->codec_id = CODEC_ID_VMDAUDIO;
        st->codec->codec_tag = 0;  /* no fourcc */
        st->codec->channels = (vmd->vmd_header[811] & 0x80) ? 2 : 1;
        st->codec->sample_rate = vmd->sample_rate;
        st->codec->block_align = AV_RL16(&vmd->vmd_header[806]);
        if (st->codec->block_align & 0x8000)
        {
            st->codec->bits_per_coded_sample = 16;

static int flic_read_header(AVFormatContext *s,
                            AVFormatParameters *ap)
{
    FlicDemuxContext *flic = s->priv_data;
    AVIOContext *pb = s->pb;
    unsigned char header[FLIC_HEADER_SIZE];
    AVStream *st, *ast;
    int speed;
    int magic_number;
    unsigned char preamble[FLIC_PREAMBLE_SIZE];

    flic->frame_number = 0;

    /* load the whole header and pull out the width and height */
    if (avio_read(pb, header, FLIC_HEADER_SIZE) != FLIC_HEADER_SIZE)
        return AVERROR(EIO);

    magic_number = AV_RL16(&header[4]);
    speed = AV_RL32(&header[0x10]);
    if (speed == 0)
        speed = FLIC_DEFAULT_SPEED;

    /* initialize the decoder streams */
    st = av_new_stream(s, 0);
    if (!st)
        return AVERROR(ENOMEM);
    flic->video_stream_index = st->index;
    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codec->codec_id = CODEC_ID_FLIC;
    st->codec->codec_tag = 0;  /* no fourcc */
    st->codec->width = AV_RL16(&header[0x08]);
    st->codec->height = AV_RL16(&header[0x0A]);

    if (!st->codec->width || !st->codec->height) {
        /* Ugly hack needed for the following sample: */
        /* http://samples.mplayerhq.hu/fli-flc/fli-bugs/specular.flc */
        av_log(s, AV_LOG_WARNING,
               "File with no specified width/height. Trying 640x480.\n");
        st->codec->width  = 640;
        st->codec->height = 480;
    }

    /* send over the whole 128-byte FLIC header */
    st->codec->extradata_size = FLIC_HEADER_SIZE;
    st->codec->extradata = av_malloc(FLIC_HEADER_SIZE);
    memcpy(st->codec->extradata, header, FLIC_HEADER_SIZE);

    /* peek at the preamble to detect TFTD videos - they seem to always start with an audio chunk */
    if (avio_read(pb, preamble, FLIC_PREAMBLE_SIZE) != FLIC_PREAMBLE_SIZE) {
        av_log(s, AV_LOG_ERROR, "Failed to peek at preamble\n");
        return AVERROR(EIO);
    }

    avio_seek(pb, -FLIC_PREAMBLE_SIZE, SEEK_CUR);

    /* Time to figure out the framerate:
     * If the first preamble's magic number is 0xAAAA then this file is from
     * X-COM: Terror from the Deep. If on the other hand there is a FLIC chunk
     * magic number at offset 0x10 assume this file is from Magic Carpet instead.
     * If neither of the above is true then this is a normal FLIC file.
     */
    if (AV_RL16(&preamble[4]) == FLIC_TFTD_CHUNK_AUDIO) {
        /* TFTD videos have an extra 22050 Hz 8-bit mono audio stream */
        ast = av_new_stream(s, 1);
        if (!ast)
            return AVERROR(ENOMEM);

        flic->audio_stream_index = ast->index;

        /* all audio frames are the same size, so use the size of the first chunk for block_align */
        ast->codec->block_align = AV_RL32(&preamble[0]);
        ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        ast->codec->codec_id = CODEC_ID_PCM_U8;
        ast->codec->codec_tag = 0;
        ast->codec->sample_rate = FLIC_TFTD_SAMPLE_RATE;
        ast->codec->channels = 1;
        ast->codec->sample_fmt = AV_SAMPLE_FMT_U8;
        ast->codec->bit_rate = st->codec->sample_rate * 8;
        ast->codec->bits_per_coded_sample = 8;
        ast->codec->channel_layout = AV_CH_LAYOUT_MONO;
        ast->codec->extradata_size = 0;

        /* Since the header information is incorrect we have to figure out the
         * framerate using block_align and the fact that the audio is 22050 Hz.
         * We usually have two cases: 2205 -> 10 fps and 1470 -> 15 fps */
        av_set_pts_info(st, 64, ast->codec->block_align, FLIC_TFTD_SAMPLE_RATE);
        av_set_pts_info(ast, 64, 1, FLIC_TFTD_SAMPLE_RATE);
    } else if (AV_RL16(&header[0x10]) == FLIC_CHUNK_MAGIC_1) {
        av_set_pts_info(st, 64, FLIC_MC_SPEED, 70);

        /* rewind the stream since the first chunk is at offset 12 */
        avio_seek(pb, 12, SEEK_SET);

        /* send over abbreviated FLIC header chunk */
        av_free(st->codec->extradata);
        st->codec->extradata_size = 12;
        st->codec->extradata = av_malloc(12);
        memcpy(st->codec->extradata, header, 12);

    } else if (magic_number == FLIC_FILE_MAGIC_1) {
//.........这里部分代码省略.........

static int flic_read_packet(AVFormatContext *s,
                            AVPacket *pkt)
{
    FlicDemuxContext *flic = s->priv_data;
    AVIOContext *pb = s->pb;
    int packet_read = 0;
    unsigned int size;
    int magic;
    int ret = 0;
    unsigned char preamble[FLIC_PREAMBLE_SIZE];

    while (!packet_read) {

        if ((ret = avio_read(pb, preamble, FLIC_PREAMBLE_SIZE)) !=
            FLIC_PREAMBLE_SIZE) {
            ret = AVERROR(EIO);
            break;
        }

        size = AV_RL32(&preamble[0]);
        magic = AV_RL16(&preamble[4]);

        if (((magic == FLIC_CHUNK_MAGIC_1) || (magic == FLIC_CHUNK_MAGIC_2)) && size > FLIC_PREAMBLE_SIZE) {
            if (av_new_packet(pkt, size)) {
                ret = AVERROR(EIO);
                break;
            }
            pkt->stream_index = flic->video_stream_index;
            pkt->pts = flic->frame_number++;
            pkt->pos = avio_tell(pb);
            memcpy(pkt->data, preamble, FLIC_PREAMBLE_SIZE);
            ret = avio_read(pb, pkt->data + FLIC_PREAMBLE_SIZE,
                size - FLIC_PREAMBLE_SIZE);
            if (ret != size - FLIC_PREAMBLE_SIZE) {
                av_free_packet(pkt);
                ret = AVERROR(EIO);
            }
            packet_read = 1;
        } else if (magic == FLIC_TFTD_CHUNK_AUDIO) {
            if (av_new_packet(pkt, size)) {
                ret = AVERROR(EIO);
                break;
            }

            /* skip useless 10B sub-header (yes, it's not accounted for in the chunk header) */
            avio_skip(pb, 10);

            pkt->stream_index = flic->audio_stream_index;
            pkt->pos = avio_tell(pb);
            ret = avio_read(pb, pkt->data, size);

            if (ret != size) {
                av_free_packet(pkt);
                ret = AVERROR(EIO);
            }

            packet_read = 1;
        } else {
            /* not interested in this chunk */
            avio_skip(pb, size - 6);
        }
    }

    return ret;
}

static int
avs_decode_frame(AVCodecContext * avctx,
                 void *data, int *data_size, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    const uint8_t *buf_end = avpkt->data + avpkt->size;
    int buf_size = avpkt->size;
    AvsContext *const avs = avctx->priv_data;
    AVFrame *picture = data;
    AVFrame *const p = (AVFrame *) & avs->picture;
    const uint8_t *table, *vect;
    uint8_t *out;
    int i, j, x, y, stride, vect_w = 3, vect_h = 3;
    AvsVideoSubType sub_type;
    AvsBlockType type;
    GetBitContext change_map;

    if (avctx->reget_buffer(avctx, p)) {
        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
        return -1;
    }
    p->reference = 1;
    p->pict_type = AV_PICTURE_TYPE_P;
    p->key_frame = 0;

    out = avs->picture.data[0];
    stride = avs->picture.linesize[0];

    if (buf_end - buf < 4)
        return AVERROR_INVALIDDATA;
    sub_type = buf[0];
    type = buf[1];
    buf += 4;

    if (type == AVS_PALETTE) {
        int first, last;
        uint32_t *pal = (uint32_t *) avs->picture.data[1];

        first = AV_RL16(buf);
        last = first + AV_RL16(buf + 2);
        if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first))
            return AVERROR_INVALIDDATA;
        buf += 4;
        for (i=first; i<last; i++, buf+=3)
            pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);

        sub_type = buf[0];
        type = buf[1];
        buf += 4;
    }

    if (type != AVS_VIDEO)
        return -1;

    switch (sub_type) {
    case AVS_I_FRAME:
        p->pict_type = AV_PICTURE_TYPE_I;
        p->key_frame = 1;
    case AVS_P_FRAME_3X3:
        vect_w = 3;
        vect_h = 3;
        break;

    case AVS_P_FRAME_2X2:
        vect_w = 2;
        vect_h = 2;
        break;

    case AVS_P_FRAME_2X3:
        vect_w = 2;
        vect_h = 3;
        break;

    default:
      return -1;
    }

    if (buf_end - buf < 256 * vect_w * vect_h)
        return AVERROR_INVALIDDATA;
    table = buf + (256 * vect_w * vect_h);
    if (sub_type != AVS_I_FRAME) {
        int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
        if (buf_end - table < map_size)
            return AVERROR_INVALIDDATA;
        init_get_bits(&change_map, table, map_size * 8);
        table += map_size;
    }

    for (y=0; y<198; y+=vect_h) {
        for (x=0; x<318; x+=vect_w) {
            if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
                if (buf_end - table < 1)
                    return AVERROR_INVALIDDATA;
                vect = &buf[*table++ * (vect_w * vect_h)];
                for (j=0; j