[mythtv-users] RFC: backend on-the-fly transcode (BOT)

[Michael T. Dean]

On 04/17/2007 06:38 PM, Stroller wrote:
> On 17 Apr 2007, at 17:13, Yan Seiner wrote:
>   
>> ...
>> I'm thinking of a on-the-fly transcode that the backend would use to
>> reduce the resolution so it's suitable for the frontend.
>>
>> This would let me use some of my lower-powered FEs to display HD  
>> content
>> - albeit at a reduced resolution...
>>     
> I've been thinking about this for a while, myself.
>
> I'm (obviously?) not qualified to code it, tho', and was a bit  
> disappointed to read the negative responses posted already. I guess  
> Mike's reasoning is sound, tho' - he certainly

pretends to ;)

>  knows far more about  
> Myth than I do.
>
> I prefer the idea of backend on-the-fly transcoding (BOT) to having  
> to keep multiple copies of the same program in storage. I'm the son  
> of a Scott and a Lancastrian, though, so maybe I'm just a skinflint  
> about storage space.  ;)
>
> If, as Mike observes, skipping/jumping/fast-forwarding/rewinding was  
> to be a problem then ideally my SD frontend would complain "woah!  
> your recorded this in HD... buffering..." whilst the backed starts to  
> transcode the HD original to SD size... the frontend would pause a  
> coupe of minutes then start - perhaps the SD version of the recording  
> could be treated like live TV?
>
> BOT would additionally allow playback of video on devices with all  
> sorts of screen-sizes - mobile phones & hand-held gameboys, for  
> instance. I actually thought that BOT was a requirement for the  
> proposed flash-based player - it's been mentioned that that would  
> answer the requests for video playback on the Wii, but I'm not sure  
> if a flash video could fill the whole browser window on the Wii,  
> enough that an SD video could fit in it.

There is work being done on it.  It's not impossible, but transcoding 
ahead of time is far easier and basically already implemented (except 
for keeping two versions in the recordings section, but you can always 
put one version in MythVideo).

I'm sorry for sounding too negative, and I'm sure those working on it 
would love the help.  I know for a fact, though, that my backends (which 
can't even do real-time commflagging of HDTV, let alone real-time 
decoding, or real-time transcoding) won't be doing any HDTV->anything 
BOT.  They'll just happily record my HDTV for my frontend to play back.

I'd love to hear people's experiences with HDTV on-the-fly transcoding.

Mike