frater secessus

frater secessus

retired snowbird

misc: IP split pea soup, processing OTA video files, holiday casuals

three-day weekends and casual campers

The quiet has been broken by an infestation of locusts casual campers that swarm every long weekend.

  • inexperienced campers struggling to set up their rigs
  • open-frame contractor generators
  • UTV louts tearing things up at 11pm1
  • loud music
  • loud conversation; if others can make out your conversation from outside your campsite you’re too loud.

cooking split peas in the Instant Pot

done

This would be more fitting for a cold winter day but turned out quite nice. I had some corn that needed cooking and found a tin of chicken I’ve been meaning to do something with.

details

processing Over The Air television video

I’m catching the programs on a cheap DVR tuner, moving the files to laptop for processing, then moving them to the OSMC pi media player.

A couple things need to be done:

  1. remove errors - OTA broadcasts have a lot of errors that you normally can’t see
  2. normalize audio - OTA digital audio is often quite low
  3. downsize to 360p to save space - 360p is fine for me and saves a ton of space

sample 480p file

Height                                   : 480 pixels
Duration                                 : 1 h 0 min
 693006336 KOB-DT2-05262023-1400.mts
 682469704 temp.mts
 247981851 KOB-DT2-05262023-1400.mts.360p.mp4

Started out at ~693MB, and the error-stripped temp file was ~682MB. Using the whole filesizes about 1.5% of the frames were removed.

After normalizing and re-encoding we are down to ~250MB/hour.

sample 1080p file

Height                                   : 1 080 pixels
Duration                                 : 31 min 52 s
2608791552 KOBDT1-05272023-2300-1.mts
2510761056 temp.mts
 194150975 KOBDT1-05272023-2300-1.mts.360p.mp4

A couple things here. 2.6GB down to ~194MB is a big reduction, and still quite watchable. It’s a half-hour show so it’s about 400MB/hour; the video is not just “taller” but also wider. I suppose I could scale it to the native width of my monitor but I have not done so yet.

Note the -1.mts suffix. This is the second half of a recording that was broken up to avoid going over the FAT32 filesize limit:

2608791552 KOBDT1-05272023-2300.mts
2608791552 KOBDT1-05272023-2300.mts1

Dorking with the extension doesn’t matter to the native tuner, but confuses things once the file leaves the reservation. So this one-liner finds and renames the problem files:

if [ -f "*.mts1" ] ; then rename 's/.mts1/-1.mts/' *.mts1; fi

sample file with dropouts

Height                                   : 480 pixels
Duration                                 : 8 h 57 min
2564591616 StartTV-05262023-2000.mts
2466128352 temp.mts
 456496983 StartTV-05262023-2000.mts.360p.mp4

This file really isn’t ~9 hours long; it’s a two hour block2 as the ~456MB final size suggests. The OTA dropouts caused file corruption that the cleaning routine couldn’t fix. Played normally in uncorrupted areas, with hangs/pixelation in the corrupted areas.

During processing the bad spots looked like this:

~~~ [mpeg2video @ 0x563773be1e00] concealing 968 DC, 968 AC, 968 MV errors in P frame StartTV-05262023-2000.mts: corrupt decoded frame in stream 0 More than 1000 frames duplicated

comments

mastodon comment thread for this post

  1. I recently heard of UTVs referred to as “douchecarts” ↩

  2. Rizzoli and Isles plus something decent that airs after it to make use of a single programming slot. ↩

Updated:

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