Block noise? when trying to send dv stream to video camera

[Hidetoshi Shimokawa]

At Fri, 02 Jul 2004 11:23:12 +0900,
Alexander Nedotsukov wrote:
> 
> Hi,
> 
> I have Sony DCR-HC40 video camera and trying to use firewire link to 
> download->edit->upload movie form it. I used fwcontrol -R test.dv 
> command to download data. Whole process went just fine. I can play raw 
> dv data and content looks correct. But if I try to send dv video (either 
> unmodified) back to the camera with fwcontrol -S test.dv command picture 
> get corrupted quickly. Corruption looks like whole image splitted into 

How log does the noise-less image last? a few seconds or shorter?

> square blocks and some parts of those blocks stay gray while
> another contains correct image. Blocks are moving. The size of blocks
> may vary. Time before video get corrupted as well from 0 to 50 sec. Do 
> you have any idea what it can be and what is much better how to fix the 
> situation?
> I running one week old -CURRENT world+kernel.
> 
> Thanks,
> Alexander.

Every DV frame has a timestamp on the packet. The DV specification
said that the timestamp must be synced with the bus cycle timer.
Some DV equipments are very sensitive to it and if it's out of sync,
we often observe block noises.

Current iso transmit code start transmit at specific bus cycle to
ensure that the timestamp must be synced at the start.
The following packets have timestamps which are calculated under
the assumption that a packet is sent for each bus cycle.
If the assumption is broken for some reason(bus is busy to transmit
a packer, the host is too slow to feed the packet and etc.),
the timestamp will be out of sync.

Do you use PAL or NTSC?

/\ Hidetoshi Shimokawa
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