diff options
| author | Marton Nemeth <nm127@freemail.hu> | 2009-10-04 18:58:19 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-12-05 21:40:27 +0100 |
| commit | 56f6f5582f7f422f142035dd92b521e72ffdb348 (patch) | |
| tree | 74224cb10bf445601bd6e876f6ce03f3c8521178 /drivers/media/video/gspca/pac7311.c | |
| parent | V4L/DVB (13120): gspca - pac7311: remove redundant register page switching (diff) | |
| download | linux-56f6f5582f7f422f142035dd92b521e72ffdb348.tar.xz linux-56f6f5582f7f422f142035dd92b521e72ffdb348.zip | |
V4L/DVB (13121): gspca - pac7311: add comment about JPEG header
Add comment about the meaning of the fixed JPEG header bytes used to
create each image.
Signed-off-by: Marton Nemeth <nm127@freemail.hu>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/media/video/gspca/pac7311.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/drivers/media/video/gspca/pac7311.c b/drivers/media/video/gspca/pac7311.c index b21c5e155f46..f954900c451b 100644 --- a/drivers/media/video/gspca/pac7311.c +++ b/drivers/media/video/gspca/pac7311.c @@ -801,13 +801,32 @@ static void do_autogain(struct gspca_dev *gspca_dev) sd->autogain_ignore_frames = PAC_AUTOGAIN_IGNORE_FRAMES; } +/* JPEG header, part 1 */ static const unsigned char pac7311_jpeg_header1[] = { - 0xff, 0xd8, 0xff, 0xc0, 0x00, 0x11, 0x08 + 0xff, 0xd8, /* SOI: Start of Image */ + + 0xff, 0xc0, /* SOF0: Start of Frame (Baseline DCT) */ + 0x00, 0x11, /* length = 17 bytes (including this length field) */ + 0x08 /* Precision: 8 */ + /* 2 bytes is placed here: number of image lines */ + /* 2 bytes is placed here: samples per line */ }; +/* JPEG header, continued */ static const unsigned char pac7311_jpeg_header2[] = { - 0x03, 0x01, 0x21, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11, 0x01, 0xff, 0xda, - 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00 + 0x03, /* Number of image components: 3 */ + 0x01, 0x21, 0x00, /* ID=1, Subsampling 1x1, Quantization table: 0 */ + 0x02, 0x11, 0x01, /* ID=2, Subsampling 2x1, Quantization table: 1 */ + 0x03, 0x11, 0x01, /* ID=3, Subsampling 2x1, Quantization table: 1 */ + + 0xff, 0xda, /* SOS: Start Of Scan */ + 0x00, 0x0c, /* length = 12 bytes (including this length field) */ + 0x03, /* number of components: 3 */ + 0x01, 0x00, /* selector 1, table 0x00 */ + 0x02, 0x11, /* selector 2, table 0x11 */ + 0x03, 0x11, /* selector 3, table 0x11 */ + 0x00, 0x3f, /* Spectral selection: 0 .. 63 */ + 0x00 /* Successive approximation: 0 */ }; /* this function is run at interrupt level */ |