diff options
| -rw-r--r-- | lib/libv4lconvert/jpeg.c | 37 |
1 files changed, 24 insertions, 13 deletions
diff --git a/lib/libv4lconvert/jpeg.c b/lib/libv4lconvert/jpeg.c index aa9cacec..0142d444 100644 --- a/lib/libv4lconvert/jpeg.c +++ b/lib/libv4lconvert/jpeg.c @@ -242,23 +242,34 @@ static int decode_libjpeg_h_samp2(struct v4lconvert_data *data, y_rows[y] = ydest; ydest += width; } - for (y = 0; y < 8; y++) { - u_rows[y] = udest; - v_rows[y] = vdest; - udest += width / 2; - vdest += width / 2; + /* + * For v_samp == 1 were going to get 1 set of uv values per + * line, but we need only 1 set per 2 lines since our output + * has v_samp == 2. We store every 2 sets in 1 line, + * effectively using the second set for each output line. + */ + if (v_samp == 1) { + for (y = 0; y < 8; y++) { + u_rows[y] = udest; + v_rows[y] = vdest; + y++; + u_rows[y] = udest; + v_rows[y] = vdest; + udest += width / 2; + vdest += width / 2; + } + } else { /* v_samp == 2 */ + for (y = 0; y < 8; y++) { + u_rows[y] = udest; + v_rows[y] = vdest; + udest += width / 2; + vdest += width / 2; + } } + y = jpeg_read_raw_data(cinfo, rows, 8 * v_samp); if (y != 8 * v_samp) return -1; - - /* For v_samp == 1 were going to get another set of uv values, - but we need only 1 set since our output has v_samp == 2, so - rewind u and vdest and overwrite the previous set. */ - if (cinfo->output_scanline % 16) { - udest -= width * 8 / 2; - vdest -= width * 8 / 2; - } } return 0; } |