Re: Why Our Civilization's Video Art and Culture is Threatened by the MPEG-LA

On 05/05/2010 10:42 AM, Basil Mohamed Gohar wrote:
> On 05/05/2010 10:09 AM, Lino Mastrodomenico wrote:
>   
>> 2010/5/4 Basil Mohamed Gohar <[email protected]>:
>>   
>>     
>>> At acceptable bitrates,
>>> e.g., 25Mbps+, at HD resolutions, MJPEG with a good quality encoder does
>>> not look significantly worse than other, more modern codecs
>>>     
>>>       
>> I'm completely out of my depth here, but isn't 25 Mbps at 1920x1080
>> and, say, 25 fps only 0.5 bits per pixel? For low complexity scenes
>> that's enough for a pretty good-looking quality, but not even close to
>> the near-losslessness that some people expect from a camcorder.
>>
>> And for high-complexity videos that's awfully too low (remember it's
>> only 125 kBytes per frame). Try e.g. compressing this image (with lots
>> of small details like the hair and the dress) down to a 125 kB JPEG:
>>
>>     http://www.mastrodomenico.eu/images/dichen.png
>>
>> Again I'm not and expert in the field, but I would expect that for
>> very good quality in worst-case scenarios a 1080p 4:2:0 MJPEG stream
>> may need 100-150 Mbps or even more, and a good denoising filter before
>> the compression.
>>   
>>     
> I did some informal testing with some HD content I've made myself, and
> 25Mbps for MJPEG wouldn't really cut it.  We'd need closer to 50Mbps to
> get something acceptable, but yeah, I think I overestimated MJPEG's
> suitability at these rates.
>   
>>   
>>     
>>> I thought about keyframe-only Theora, but then, if we're going
>>> to do that, why not just fall back to MJPEG?
>>>     
>>>       
>> One reason is that if you use Theora you can offer to the user the
>> option to switch to a full intra+inter stream with dramatically lower
>> bitrates. Plus doesn't MJPEG have a lower quality than intra-only
>> Theora?
>>
>>   
>>     
> Well, now we're talking many different things!  If we want intra-only,
> such as DiracPro or MJPEG, then intra-only Theora is a possible player,
> but having the ability to switch up to full intra+inter Theora will add
> the full complexity of the spec, so why bother with the inefficiency of
> intra-only anyway?
>
> The way I see it, if we're going to go for a freedom-friendly camcorder,
> we can have the option of supporting more than one codec (at least on a
> technical level).  Whatever hardware can do intra-only Theora, I'm
> reasonably confident can also do MJPEG as well.
>
> Having said that, as I mentioned elsewhere, I'm going to play-around
> with some intra-only Theora and see how it performs vis-a-vis MJPEG.
>   
I've done some more casual testing of intra-only Theora, and ptalarbvorm
really has some beautiful intra-only video, even at a measly 25Mbps!  I
am pulling down some 1080p clips from media.xiph.org right now to test
some more with, and I will let you guys know the results later.

Maybe we can call it TheoraPro...;)