[mythtv-users] hdhr file troubles on atv2

[belcampo]

Raymond Wagner wrote:
> On 2/15/2011 11:23, belcampo wrote:
>> belcampo wrote:
>>> belcampo wrote:
>>>> Raymond Wagner wrote:
>>>>> On 2/14/2011 09:51, David Evans wrote:
>>>>>> I picked up a atv2 about a week ago and I have been tinkering with it.
>>>>>>    I have xbmc running on it and using the built in myth:// protocol I
>>>>>> can play SD files without any trouble.  The issue that I am having is
>>>>>> with files produced by the hdhr.  They will load up but I get a severe
>>>>>> stutter with the audio and they are unwatchable.  I tried loading the
>>>>>> files via a smb mount and I get constant buffering.
>>>>>>
>>>>>> I figured the solution would be to transcode the files down to a mpeg4
>>>>>> format that should be easier for the ATV2 to play but I'm struggling
>>>>>> with the settings of mythtranscode to get a file that plays cleanly.
>>>>>> If I could get any insight it would be great.
>>>>> The ATV2 does not support hardware acceleration of the MPEG2 output by a
>>>>> digital tuner, nor the HD MPEG4 output by mythtranscode.  That means you
>>>>> are relying on the woefully inadequate 1GHz ARM for software decoding.
>>>>> Until XBMC has fully explored the VideoToolBox API and documented what
>>>>> the device is actually capable of, rather than what Apple has restricted
>>>>> the device to, the only authoritative reference on the decoding
>>>>> performance of that device is on the Apple site.
>>>> I do have one for 2 weeks and it can play BluRay as input-format.
>>>> I use makemkv to get the BD in a matroska container which I then serve
>>>> with minidlna to upnp to XBMC on the atv2, although it scales it down to
>>>> 720p, but further it works very well.
>>> Sorry I was too hasty, I had encoded them to 1080p but at a lower
>>> bitrate with ffmpeg -crf 24, which resulted in visibly perfect,
>>> according to mediainfo:
>>> Overall bit rate                 : 6 143 Kbps
>> Again too fast, I used -cqp 24
>> instead of -crf 24
> 
> In case anyone wants to follow suit, a quantizer of 18 is considered 
> effectively lossless, and 20 or under good enough that most people will 
> not notice any artifacts on a moving image, only stills.  A quantizer of 
> 24 is considered 'medium quality' and will result in artifacts and 
> blurring visible by most people even during playback.  There is good 
> reason why Bluray video typically runs at upwards of 30Mbps, rather than 6.
Bits ain't always Bit's. Gzip-slow does a better job then Gzip-fast on 
compressing a textfile.
X264 is one of the best encoders around, if not the best.
A Russian H264 comparison-site, haven't the name of it right now, showes 
that there are VERY BIG differences in the bitrate when quality is the 
same. In previous years some BIG-names where attending and the results 
where ......
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