[mythtv-users] Two odd issues with NBC DTV recordings

[Tom Dexter]

On Wed, Oct 1, 2008 at 10:23 PM, Brad DerManouelian
<myth at dermanouelian.com> wrote:
> On Oct 1, 2008, at 7:14 PM, Kevin Kuphal wrote:
>
> On Wed, Oct 1, 2008 at 5:32 PM, Tom Dexter <digitalaudiorock at gmail.com>
> wrote:
>>
>> I record OTA DTV broadcast out of New York City.  Over the past couple
>> of weeks I've noticed two issues that only occur with recordings from
>> NBC (channel 4.1)...nothing serious but odd.  I already know that NBC
>> is notorious for strange things like switching frame rates for
>> commercials and missing progressive and interlaced frames etc...maybe
>> this stuff is related.  The issues are only on recordings from the
>> past few weeks and don't occur with what older NBC recordings I have.
>> I've done no updates to anything in that time.
>>
>> First of all, very often when I jump ahead or back in the recording I
>> get temporary pixelation, almost as though it's not finding a key
>> frame or something.
>
> I've noticed the same thing on our NBC HD recordings here near Chicago via
> QAM cable.
>
> I've always gotten that on my NBC recordings and chalked it up to "that's
> how 1080i content is" since I don't have any other 1080i station to compare
> it to.
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I actually have CBS, the WB, and PBS that are all 1080i and don't have
this issue.  I get an almost unnoticeable pilexation when jumping on
some other programs, but on these recent NBC recordings it can take a
full second or two to clear up.  It sometimes appears to start with
the old frame that I jumped from, like it's assembling the picture
with no starting key frame.

I noticed that I'm getting some "first frame is no keyframe" errors on
the backend during commflagging:

2008-10-01 03:10:59.898 [mpeg2video @ 0xb7306028]warning: first frame
is no keyframe
2008-10-01 03:11:01.567 [mpeg2video @ 0xb7306028]warning: first frame
is no keyframe
2008-10-01 03:11:18.429 [mpeg2video @ 0xb7306028]warning: first frame
is no keyframe
2008-10-01 03:11:24.902 [mpeg2video @ 0xb7306028]warning: first frame
is no keyframe

I believe they're from NBC recordings as well.

Thanks for all the replies.  Good to know I'm not the only one seeing
this though.

Tom