static int bethsoftvid_decode_frame(AVCodecContext *avctx,
                              void *data, int *got_frame,
                              AVPacket *avpkt)
{
    BethsoftvidContext * vid = avctx->priv_data;
    char block_type;
    uint8_t * dst;
    uint8_t * frame_end;
    int remaining = avctx->width;          // number of bytes remaining on a line
    int wrap_to_next_line;
    int code, ret;
    int yoffset;

    if ((ret = ff_reget_buffer(avctx, vid->frame)) < 0)
        return ret;
    wrap_to_next_line = vid->frame->linesize[0] - avctx->width;

    if (avpkt->side_data_elems > 0 &&
        avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
        bytestream2_init(&vid->g, avpkt->side_data[0].data,
                         avpkt->side_data[0].size);
        if ((ret = set_palette(vid)) < 0)
            return ret;
    }

    bytestream2_init(&vid->g, avpkt->data, avpkt->size);
    dst = vid->frame->data[0];
    frame_end = vid->frame->data[0] + vid->frame->linesize[0] * avctx->height;

    switch(block_type = bytestream2_get_byte(&vid->g)){
        case PALETTE_BLOCK: {
            *got_frame = 0;
            if ((ret = set_palette(vid)) < 0) {
                av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
                return ret;
            }
            return bytestream2_tell(&vid->g);
        }
        case VIDEO_YOFF_P_FRAME:
            yoffset = bytestream2_get_le16(&vid->g);
            if(yoffset >= avctx->height)
                return AVERROR_INVALIDDATA;
            dst += vid->frame->linesize[0] * yoffset;
    }

    // main code
    while((code = bytestream2_get_byte(&vid->g))){
        int length = code & 0x7f;

        // copy any bytes starting at the current position, and ending at the frame width
        while(length > remaining){
            if(code < 0x80)
                bytestream2_get_buffer(&vid->g, dst, remaining);
            else if(block_type == VIDEO_I_FRAME)
                memset(dst, bytestream2_peek_byte(&vid->g), remaining);
            length -= remaining;      // decrement the number of bytes to be copied
            dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
            remaining = avctx->width;
            if(dst == frame_end)
                goto end;
        }

        // copy any remaining bytes after / if line overflows
        if(code < 0x80)
            bytestream2_get_buffer(&vid->g, dst, length);
        else if(block_type == VIDEO_I_FRAME)
            memset(dst, bytestream2_get_byte(&vid->g), length);
        remaining -= length;
        dst += length;
    }
    end:

    if ((ret = av_frame_ref(data, vid->frame)) < 0)
        return ret;

    *got_frame = 1;

    return avpkt->size;
}
Exemple #2
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static int decode_frame(AVCodecContext *avctx,
                        void *data, int *data_size,
                        AVPacket *avpkt)
{
    PicContext *s = avctx->priv_data;
    uint32_t *palette;
    int bits_per_plane, bpp, etype, esize, npal, pos_after_pal;
    int i, x, y, plane, tmp;

    bytestream2_init(&s->g, avpkt->data, avpkt->size);

    if (bytestream2_get_bytes_left(&s->g) < 11)
        return AVERROR_INVALIDDATA;

    if (bytestream2_get_le16u(&s->g) != 0x1234)
        return AVERROR_INVALIDDATA;

    s->width       = bytestream2_get_le16u(&s->g);
    s->height      = bytestream2_get_le16u(&s->g);
    bytestream2_skip(&s->g, 4);
    tmp            = bytestream2_get_byteu(&s->g);
    bits_per_plane = tmp & 0xF;
    s->nb_planes   = (tmp >> 4) + 1;
    bpp            = bits_per_plane * s->nb_planes;
    if (bits_per_plane > 8 || bpp < 1 || bpp > 32) {
        av_log_ask_for_sample(s, "unsupported bit depth\n");
        return AVERROR_INVALIDDATA;
    }

    if (bytestream2_peek_byte(&s->g) == 0xFF) {
        bytestream2_skip(&s->g, 2);
        etype = bytestream2_get_le16(&s->g);
        esize = bytestream2_get_le16(&s->g);
        if (bytestream2_get_bytes_left(&s->g) < 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;

    pos_after_pal = bytestream2_tell(&s->g) + esize;
    palette = (uint32_t*)s->frame.data[1];
    if (etype == 1 && esize > 1 && bytestream2_peek_byte(&s->g) < 6) {
        int idx = bytestream2_get_byte(&s->g);
        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++) {
            int pal_idx = bytestream2_get_byte(&s->g);
            palette[i]  = ff_cga_palette[FFMIN(pal_idx, 16)];
        }
    } else if (etype == 3) {
        npal = FFMIN(esize, 16);
        for (i = 0; i < npal; i++) {
            int pal_idx = bytestream2_get_byte(&s->g);
            palette[i]  = ff_ega_palette[FFMIN(pal_idx, 63)];
        }
    } else if (etype == 4 || etype == 5) {
        npal = FFMIN(esize / 3, 256);
        for (i = 0; i < npal; i++)
            palette[i] = bytestream2_get_be24(&s->g) << 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);
    // skip remaining palette bytes
    bytestream2_seek(&s->g, pos_after_pal, SEEK_SET);

    x = 0;
    y = s->height - 1;
    plane = 0;
    if (bytestream2_get_le16(&s->g)) {
        while (bytestream2_get_bytes_left(&s->g) >= 6) {
            int stop_size, marker, t1, t2;

            t1        = bytestream2_get_bytes_left(&s->g);
            t2        = bytestream2_get_le16(&s->g);
            stop_size = t1 - FFMIN(t1, t2);
            // ignore uncompressed block size
            bytestream2_skip(&s->g, 2);
            marker    = bytestream2_get_byte(&s->g);

            while (plane < s->nb_planes &&
                   bytestream2_get_bytes_left(&s->g) > stop_size) {
                int run = 1;
                int val = bytestream2_get_byte(&s->g);
                if (val == marker) {
                    run = bytestream2_get_byte(&s->g);
                    if (run == 0)
                        run = bytestream2_get_le16(&s->g);
                    val = bytestream2_get_byte(&s->g);
                }
                if (!bytestream2_get_bytes_left(&s->g))
                    break;

                if (bits_per_plane == 8) {
                    picmemset_8bpp(s, val, run, &x, &y);
                    if (y < 0)
                        break;
                } else {
                    picmemset(s, val, run, &x, &y, &plane, bits_per_plane);
                }
            }
        }
    } else {
        av_log_ask_for_sample(s, "uncompressed image\n");
        return avpkt->size;
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = s->frame;
    return avpkt->size;
}