[mythtv] Slave backend using different encodings specs
thormj at ieee.org
Mon Mar 24 20:31:11 EST 2003
>> In other words, the profile field in the record table represents,
>> say 0=Default, 1=(same as) LiveTV, 2=Best quality, 3=Save Disk
>> Space, etc. Another table could then associate these with
>> specific codecparams for a class of cards. For most people
>> with one tuner, dual equivalent tuners, multiple backends with
>> similar resources, they would only need one class and profile
>> 0 (Default) is associated with codecparams 0. They would only
>> need to enter these once, as we do now, rather than per host.
>> If they added an MJPEG or future HDTV, DVB, or hardware mpeg2
>> card they could add a new class for these cards so that Default
>> (0) is associated with codecparams 4, LiveTV (1) with params 5
>> and so on. Any number of card classes could be created and
>> any cardinputid could be associated with any class.
>This is more or less what I was suggesting; I'm not sure that it makes
>to do it in every case, as a complete additional layer of indirection,
>however. I think that two settings or so would be sufficient, and much
>simpler. For example, one setting for the default profile for recording,
>and another setting for the default profile for Live TV. Since we have
>per-host settings, this would also provide for different defaults for
>different systems. Eventually, perhaps, it will be possible to explicitly
>set the scope of a profile (per-host or global).
>I'm not convinced that the type of capture card is a useful criteria,
>in the case of hardware MJPEG. CPU resources, storage resources, output
>device, and input quality would probably be more significant (in that
>order), don't you think?
How about a field like "CompatCodecParms" added to the capturecard
table that would indicate which capturecards could perform which codec
settings best. The indirection is easier to handle, but picking a "Default"
gets harder (maybe... maybe not.). This would also allow heterogenous
backends (e.g. slowhost can't handle a mpeg4 bitrate of > 1000). 'Course
until the "recordings" get linked with "codecparms", the user has no
idea what kind of encoding/quality the operation will be performed at...
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