On 05/07/2019 16:54, Pancho wrote:
> On 05/07/2019 10:43, James Harris wrote:
>> On 05/07/2019 10:20, A. Dumas wrote:
>>> James Harris  wrote:
>>>> On 03/07/2019 17:27, Pancho wrote:
>>>>> Hi I've just tried using a Pi 4 4GB under Raspbian. The answer is that
>>>>> whilst it is undoubtedly very impressive it isn't good enough for a
>>>>> general purpose desktop.
>>>>>
>>>>>
>>>>> The good:
>>>>>
>>>>> * Chromium browsing not featuring video was good. Perhaps a bit slow
>>>>> but
>>>>> not annoyingly so.
>>>>> * vlc could play x264 video perfectly at 1080p, at about 5% cpu.
>>>>> * Generally apps/windows opened at an OK speed.
>>>>>
>>>>> The bad:
>>>>>
>>>>> * vlc was poor at playing x265 at 1080p, jerky, 50% cpu and about 30%
>>>>> dropped frames.
>>>>> * Youtube video was awful, slow, jerky. As were other, popular, free
>>>>> video Streaming sites.
>>>>> * Amazon Video wouldn't play at all due to chromium not being a
>>>>> supported browser.
>>>>> * LibreOffice Calc gave painfully slow scrolling, on a sheet with 365
>>>>> rows and 26 columns.
>>
>> ...
>>
>>>> Thanks for the above info. I wanted to move to a 4k desktop when I saw
>>>> the RPi4 announcement. For various reasons I will look into the idea of
>>>> mini-itx that Martin mentioned but will maybe come back to the RPi4 for
>>>> an HTPC front end to a MythTV system - at least at up to 1080p.
>>>
>>> For lack of vp9 hardware decoding, I fear the Pi4 will never be good for
>>> Youtube 4k videos. And it's a real shame they couldn't squeeze h.264
>>> hardware decoding in, so no higher than 1080p for that either. And while
>>> the cpu is capable enough to decode that, it will require active
>>> cooling, I
>>> guess.
>>>
>>
>> When you mentioned that YouTube and other videos were jerky was that
>> just the 4k ones, such that lower resolutions were OK?
>>
>
> All Youtube videos were jerky, even 720p.
>
> For clarity the Pi 4 is supposed to have hardware support for:
>
> HEVC decode to 4K@60 (with HDR) (HEVC=x265)
> H.264 decode to 1080p@60.

OK.

>
> VLC is clearly already using H.264 hardware decode at 1080. I guess HEVC
> hardware decode will come with time. I haven't seen any mention of vp9
> and of course av1 is a potential in the near future.

I'm not sure I understand that. Do you mean that the Pi has hardware
which will do - or will help with - HEVC decode but VLC doesn't take
advantage of it yet?

>
> The main problem is that Chromium isn't using gpu support.
>
> I could show the output of typing chrome://gpu into chromium, if anyone
> is interested.

Please do.

>
> Generally, I'm very sceptical of the need for 4k video.
>
> I can understand someone wanting a 4k monitor. I've used a 30 inch
> 2560x1600 monitor for years and it is better than 1900*1080. I guess
> sitting 50cm from a 40 inch monitor at 4k would make a difference but I
> can't see that it would make a difference at TV distances. Anyway, if I
> was going to do that I would use something better than a Pi 4.
>

I find HD and UHD look very similar on TV. In fact, the first time I saw
a 4k programme it looked awful - clearly something else wrong with that
particular programme. Watching some 4k tennis the other day it looked
almost no different from the same tennis on HD.

But this is for computer use. My monitor is 26" 1920*1200 ... and it's
time to upgrade!

Since 4k panels are so prevalent I guess 4k is the way to go so I went
into PC World yesterday to see some examples of what that would look
like in practice. But to my surprise they did not even have one example
of such a setup in place. 4k TVs but no 4k monitors connected to computers.


--
James Harris

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