[FFmpeg-user] Original display aspect ratio is not copied to output

[Dr. Johannes Zellner]

Hi,

I'm trying to reduce the size of some TV recordings.
What I did is something like

# avconv -threads 2 -i tv-recording.mkv -map 0 -c:v libx264 -preset
medium -tune film -crf 23 -c:a copy output.mkv

Unfortunately the output file is displayed on a Samsung TV by default
with the wrong aspect ratio while the orignal input file is displayed by
default with the correct aspect ratio.

I inspected both files with mediainfo:

# mediainfo tv-recording.mkv
...
Video
...
Format                                   : MPEG Video
...
Display aspect ratio                     : 5:4
Original display aspect ratio            : 16:9
 Active Format Description                : Full frame 16:9 image
...

# mediainfo output.mkv
...
Video
...
Format                                   : AVC
...
Display aspect ratio                     : 5:4
...

so the two lines with "Original display aspect ratio" and "Active Format
Description" are missing in the encoded output file.
I suspect that these lines are responsible for the correctly displayed
aspect ratio for the original tv-recording.mkv.

ANY IDEAS HOW TO GET THE TWO LINES COPIED TO THE OUTPUT FILE OR ANY
OTHER IDEAS HOW TO GET THE OUTPUT DISPLAYED WITH THE CORRECT ASPECT
RATIO BY DEFAULT?

Any help much appreciated.

-- 
Johannes