[mythtv-users] Preview image is only 1 pixel

Robert Johnston anaerin at gmail.com
Wed Jan 14 22:01:48 UTC 2009


2009/1/14 John Finlay <finlay at moeraki.com>:
> Michael T. Dean wrote:
>> On 01/14/2009 04:15 AM, John Finlay wrote:
>>
>>> I found a thread in the ubuntu forums that discusses the same problem I
>>> have - unusable 1x1 pixel preview image created for RTjpeg NUV files but
>>> usaable preview image after transcoding to MPEG4 NUV file.
>>>
>>> http://ubuntuforums.org/archive/index.php/t-954500.html
>>>
>>
>> If you're able to track down the bug, we'd love a patch.  Not too many
>> people are using RTJPEG/NUV these days, so it's been very low priority.
>>
> It's surprising that it is the default encoding in the recording
> profiles. I only recently started recording analog so haven't checked
> all the nooks and crannies yet. Does MPEG4 require a lot more processing
> power from a software encoder? I don't want to overload my BE.

RTJPEG is very lean in terms of CPU usage, whereas MPEG4 is very
heavy. In some cases it is possible to realtime encode MPEG4, but in
most cases it would tie up almost 100% CPU usage on a single stream.

I believe the suggested method was to record in RTJPEG, then
auto-transcode to MPEG4 (at a nice, high nice number to make it a low
priority).

Both are so rarely used these days as most preferred input methods
(HDHomeRun, DVB, ATSC, ClearQAM, IVTV, IPTV) all use either hardware
encoding, or pre-encoded streams, meaning the compression that has to
be done by the backend is essentially zero.

I believe the best way to describe analog capture in Myth is
"Deprecated, but supported".
-- 
Robert "Anaerin" Johnston


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