[mythtv-users] Increase in recorded file sizes

[Matthew McClement]

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