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>
This commit is contained in:
Родитель
0ef0289264
Коммит
aafc77066f
|
@ -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;
|
||||
|
||||
|
|
Загрузка…
Ссылка в новой задаче