static int targa_encode_normal(uint8_t *outbuf, const AVFrame *pic, int bpp, int w, int h)
{
    int i, n = bpp * w;
    uint8_t *out = outbuf;
    uint8_t *ptr = pic->data[0];

    for(i=0; i < h; i++) {
        memcpy(out, ptr, n);
        out += n;
        ptr += pic->linesize[0];
    }

    return out - outbuf;
}