[mythtvnz] Transcoding HD videos

[Pshem Kowalczyk]

Hi All,

I was wondering if anyone transcodes Freeview|HD stuff into something
less diskspace hungry? I came up with the following set of parameters
for ffmpeg for HD material (1080 to 720 and reducing the bitrate to
about 3.5Mb/s from original 10-11Mb/s, retaining the orginal mpegts
format and removing 'unknown' streams):

ffmpeg -i /data/mythtv/store/4003_20100206192900.mpg -threads 3 -map 0
-c copy -c:v:0 libx264 -s 1280x720 -map -0:3  -b:v 3500k -pass 1 -f
rawvideo -an -y /dev/null
ffmpeg -i /data/mythtv/store/4003_20100206192900.mpg -threads 3 -map 0
-c copy -c:v:0 libx264 -s 1280x720 -map -0:3  -b:v 3500k -pass 2 -f
mpegts /data/mythtv/store/4003_20100206192900.mpg.new

(after that I use mythcommflag --rebuild to rebuild the index so myth
can play it)

Unfortunately every now and then (roughly every 5-10 minutes) the
scene change is not smooth, as if the key frame got missed. It's not
terrible, but decreases the WAF a little bit every time it happens.
Anyone doing this sort of  transcoding? If so - what do you use?

kind regards
Pshem