diff options
| author | Andy Walls <awalls@radix.net> | 2008-12-14 19:21:35 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2008-12-30 09:39:07 -0200 |
| commit | aafc77066f4cc8b6de4af1a7d643c9646e19bad9 (patch) | |
| tree | 0db630a699bf8c73d93768e77144273ba65ab5a6 /drivers | |
| parent | 0ef0289264e8f278312909f1639a7764cc9cf580 (diff) | |
V4L/DVB (9892): cx18: VBI comment corrections and comments about VBI issues
VBI comment corrections to avoid future confusion about standards.
Comments on cx18 VBI implementation shortcomings that need resolution.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/video/cx18/cx18-driver.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/media/video/cx18/cx18-driver.c b/drivers/media/video/cx18/cx18-driver.c index 863ebf06a82..d7baf1b97cb 100644 --- a/drivers/media/video/cx18/cx18-driver.c +++ b/drivers/media/video/cx18/cx18-driver.c @@ -609,18 +609,21 @@ static int __devinit cx18_init_struct1(struct cx18 *cx) * We use a BT.656 pxiel clock of 13.5 MHz and a BT.656 active line * length of 720 pixels @ 4:2:2 sampling. Thus... * - * For NTSC: + * For systems that use a 15.734 kHz horizontal rate, such as + * NTSC-M, PAL-M, PAL-60, and other 60 Hz/525 line systems, we have: * - * (1/15,734 kHz) * 2 * 13.5 MHz = 1716 samples/line = + * (1/15.734 kHz) * 2 * 13.5 MHz = 1716 samples/line = * 4 bytes SAV + 268 bytes anc data + 4 bytes SAV + 1440 active samples * - * For PAL: + * For systems that use a 15.625 kHz horizontal rate, such as + * PAL-B/G/H, PAL-I, SECAM-L and other 50 Hz/625 line systems, we have: * - * (1/15,625 kHz) * 2 * 13.5 MHz = 1728 samples/line = + * (1/15.625 kHz) * 2 * 13.5 MHz = 1728 samples/line = * 4 bytes SAV + 280 bytes anc data + 4 bytes SAV + 1440 active samples * */ + /* FIXME: init these based on tuner std & modify when std changes */ /* CX18-AV-Core number of VBI samples output per horizontal line */ cx->vbi.raw_decoder_line_size = 1444; /* 4 byte SAV + 2 * 720 */ cx->vbi.sliced_decoder_line_size = 272; /* 60 Hz: 268+4, 50 Hz: 280+4 */ @@ -924,6 +927,11 @@ static int __devinit cx18_probe(struct pci_dev *dev, } cx->params.video_gop_size = cx->is_60hz ? 15 : 12; + /* + * FIXME: setting the buffer size based on the tuner standard is + * suboptimal, as the CVBS and SVideo inputs could use a different std + * and the buffer could end up being too small in that case. + */ vbi_buf_size = cx->vbi.raw_size * (cx->is_60hz ? 24 : 36) / 2; cx->stream_buf_size[CX18_ENC_STREAM_TYPE_VBI] = vbi_buf_size; |