static void qtrle_decode_16bpp(QtrleContext *s) { int stream_ptr; int header; int start_line; int lines_to_change; signed char rle_code; int row_ptr, pixel_ptr; int row_inc = s->frame.linesize[0]; unsigned short rgb16; unsigned char *rgb = s->frame.data[0]; int pixel_limit = s->frame.linesize[0] * s->avctx->height; /* check if this frame is even supposed to change */ if (s->size < 8) return; /* start after the chunk size */ stream_ptr = 4; /* fetch the header */ CHECK_STREAM_PTR(2); header = BE_16(&s->buf[stream_ptr]); stream_ptr += 2; /* if a header is present, fetch additional decoding parameters */ if (header & 0x0008) { CHECK_STREAM_PTR(8); start_line = BE_16(&s->buf[stream_ptr]); stream_ptr += 4; lines_to_change = BE_16(&s->buf[stream_ptr]); stream_ptr += 4; } else { start_line = 0; lines_to_change = s->avctx->height; } row_ptr = row_inc * start_line; while (lines_to_change--) { CHECK_STREAM_PTR(2); pixel_ptr = row_ptr + (s->buf[stream_ptr++] - 1) * 2; while ((rle_code = (signed char)s->buf[stream_ptr++]) != -1) { if (rle_code == 0) { /* there's another skip code in the stream */ CHECK_STREAM_PTR(1); pixel_ptr += (s->buf[stream_ptr++] - 1) * 2; CHECK_PIXEL_PTR(0); /* make sure pixel_ptr is positive */ } else if (rle_code < 0) { /* decode the run length code */ rle_code = -rle_code; CHECK_STREAM_PTR(2); rgb16 = BE_16(&s->buf[stream_ptr]); stream_ptr += 2; CHECK_PIXEL_PTR(rle_code * 2); while (rle_code--) { *(unsigned short *)(&rgb[pixel_ptr]) = rgb16; pixel_ptr += 2; } } else { CHECK_STREAM_PTR(rle_code * 2); CHECK_PIXEL_PTR(rle_code * 2); /* copy pixels directly to output */ while (rle_code--) { rgb16 = BE_16(&s->buf[stream_ptr]); stream_ptr += 2; *(unsigned short *)(&rgb[pixel_ptr]) = rgb16; pixel_ptr += 2; } } } row_ptr += row_inc; } }