[mythtv-users] HD-PVR Max quality settings?

Greg Oliver oliver.greg at gmail.com
Mon Jan 25 18:44:27 UTC 2010


On Sun, Jan 24, 2010 at 5:18 PM, John P Poet <jppoet at gmail.com> wrote:
> On Sun, Jan 24, 2010 at 4:09 PM, Christopher Meredith
> <chmeredith at gmail.com> wrote:
>> On Sun, Jan 24, 2010 at 5:06 PM, John P Poet <jppoet at gmail.com> wrote:
>>> On Sun, Jan 24, 2010 at 3:40 PM, Christopher Meredith
>>> <chmeredith at gmail.com> wrote:
>>>> I'm not entire sure how to test how recording profiles work because
>>>> I've never used them, but I want the HD-PVR to record at its highest
>>>> possible quality setting. I am doing lossy commercial cutting so I
>>>> need the source to be as high quality as possible. Because I wasn't
>>>> sure what I was doing, I went into all the recording profiles and
>>>> moved all the sliders to max. This did make the resulting recordings
>>>> larger and some were noticeably better quality, but it seems to be
>>>> inconsistent. For example, I recorded the pilot of Caprica off Syfy
>>>> and it was noticeably blocky in dark scenes and accroding to
>>>> mediainfo, the video bitrate was a paltry 4617 Kbps, which seems to me
>>>> to be about 1/3 of the box's capabilities.
>>>>
>>>> Is there a "right" way to make the HD-PVR go balls to the wall?
>>>
>>> Using CBR will give you higher bitrate than VBR.  To get CBR, set the
>>> peak to be *less* than the average.
>>>
>>> That being said, the quality is also highly dependent on the source.
>>
>> Thanks John. Would this produce different behavior than having the
>> peak and average set to the same value?
>
> If the peak is detected to be less than the average, that triggers CBR
> mode using the average value for the bitrate.  In CBR mode, the peak
> value is ignored.
>
> Once the setup screens are converted to MythUI, I intend to re-work
> that screen so it is more obvious how to toggle VBR/CBR.
>

So reading this, am I to assume that setting all of the from the
command line using the v4l2 tools that they are overwritten by mythtv
anyhow?  I could not find screens to set them in mythtv, so I have a
script to set them at bootup.  But it sounds that it may not make a
difference.

I guess I am just looking at the best way to set them in .22

Thanks,

Greg


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