On 06/08/2009 04:36 PM, Devin Heitmueller wrote:
On Mon, Jun 8, 2009 at 4:20 PM, Steven Toth<st...@kernellabs.com> wrote:
We're getting into the realm of 'do you need to amplify and/or debug your
cable network', and out of the realm of driver development.
Comcast is coming tomorrow to check out the signal quality. They said
that they expect to deliver SNR in the range of 33dB - 45dB to the
premises. I will let you know how that affects Linux captures.
Steven,
One thing that is interesting is that he is getting BER/UNC errors
even on ATSC, when he has a 30.2 dB signal. While I agree that the
cable company could be sending a weak signal, 30 dB should be plenty
for ATSC.
Also, it's possible that the playback application/codec in question
poorly handles recovery from MPEG errors such as discontinuity, which
results in the experience appearing to be worse under Linux.
I am actually comparing the TS files captured under both Linux and
Windows side-by-side in the same environment, copying the files to other
computers in my home. I can demux the video with Project-X which prints
out the errors in the bitstream as it reads them. I can also observe
the overall quality by playing it back with VLC, WinDVD, etc. When I
use TMPGEnc Authoring Works 4 to read the file, the errors in the
bitstream even seem to crash the application -- though obviously TMPGEnc
is to blame for that.
I'm going to see if I can find some cycles to do some testing here
with s5h1409/s5h1411 and see if I can reproduce what David is seeing.
Devin, I would really really appreciate this. I hesitated to e-mail
this list for several weeks, because I wanted to investigate thoroughly
first and avoid wasting anyone's time as much as possible. I hope you
are able to reproduce this.
David
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