[mythtv-users] Increase in recorded file sizes

[John Pilkington]

Matthew McClement wrote:
> Mike Perkins wrote:
>> Gordon McCrae wrote:
>>> Actually, I've always had this (for the last year) without and now
>>> with multirec. The BBC streams are higher rates / resolution than
>>> some other channels. If you play the .mpg file with mplayer, it'll
>>> tell you the mitrate, resolution etc. I especially notice that
>>> channels like E4 transmit in some odd resolutions like 540x400 etc,
>>> depends on the programme, time of day etc.
>>>
>> I've only noticed this happening the last two weeks. Is it possible
>> for different transmitters to offer different bit rates? I'm probably
>>  grasping at straws, but I'm trying to figure out what's different.
>>
>> This only seems to have happened (for me) since the multirec code 
>> activated itself.
> 
> Bitrates will vary from transmitter to transmitter and from timeslot to 
> timeslot. The BBC channels definately have a higher bitrate than 
> anything else however, as the following bit of atrocious SQL demonstrates:
> 
> mysql> SELECT c.callsign, 
> AVG((r.filesize/1024/1024)/(TIME_TO_SEC(TIMEDIFF(r.progend,r.progstart))/60/60)) 
> AS MBytePerHour FROM recorded AS r JOIN channel AS c ON r.chanid = 
> c.chanid  GROUP BY c.callsign ORDER BY MBytePerHour;
> +-----------+-----------------------+
> | callsign  | MBytePerHour          |
> +-----------+-----------------------+
> | Film4     | 1256.1109891145130000 |
> | Dave      | 1572.9996911652234762 |
> | ITV3      | 1788.8391819978370000 |
> | E4        | 1801.8339177911930000 |
> | Channel 4 | 2003.3352870941165000 |
> | ITV1      | 2158.3057354018532692 |
> | ITV2      | 2166.5138244628910000 |
> | BBC THREE | 2242.9232841491700000 |
> | BBC FOUR  | 2881.7079391479490000 |
> | BBC TWO   | 3006.7467575073240000 |
> | BBC ONE   | 3155.6208727688140968 |
> +-----------+-----------------------+
> 11 rows in set (0.00 sec)
> 
> (you can get the min and max bitrates for a channel by changing AVG in 
> the above to MIN or MAX)
> 
> BBC1 has bitrates that vary from 3GB/hour all the way up to 
> 4.3GB/hour(!). The high bitrate recordings appear to be Points of View, 
> bizarrely, with Rachel Allen's Bake making second at 3.5GB/hour.
> 
> The "Jonathan Creek Christmas Special", as a contrast, only got 
> 2.7GB/hour on BBC1.
> 
> Perhaps your regular recordings have gotten a bitrate bump as of late?
> 
> Matt

A change in the recording profile is perhaps the most likely cause of a 
sudden change in recorded bitrate.

Frontend > Setup > TV settings > Recording Profiles > Hardware DVB 
Encoders > Default > Recording Type > Normal/TV only/Audio only

'Normal' will record interactive stuff as well as the main channel - but 
maybe only if you have 'interactive TV' enabled in the 'Playback OSD' 
menu.  These settings might perhaps have got changed in the card-reshuffle?

I liked the use of SQL here.

John P