Mailing List Archive

Recording quality
My next issue is with playback quality. My recordings in mythtv are
watchable, but the quality is relatively poor. Recording from the command
line using ffmpegrec from NVrec:

ffmpegrec -v /dev/video0 -w 640 -h 480 -vb 2200 -vc mpeg4 -o test.avi

which results in a quality factor of about 10, looks excellent when played
back using mplayer. However, mythtv using these settings:

int TargetBitrate=2200
int ScaleBitrate=0
int MaxQuality=2
int MinQuality=15
int QualDiff=3

looks bad in comparison; there is a lot of pixellation and the colour looks
washed-out. Since both are using libavcodec, I would expect their output to
be much more similar.

As you can see, there are a lot of variables here, including the fact that
different engines are used for playback. It would be much easier to compare
if I could playback mythtv recordings using mplayer. It already understands
NuppelVideo format, but not in conjunction with mpeg4...vektor in #mythtv
said that this would probably not be difficult to implement; can anyone give
me some pointers as to what would be required?

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- mdz
Re: Recording quality [ In reply to ]
On Sun, Oct 20, 2002 at 11:43:53PM -0400, Matt Zimmerman wrote:

> looks bad in comparison; there is a lot of pixellation and the colour looks
> washed-out. Since both are using libavcodec, I would expect their output to
> be much more similar.

In case anyone else runs into a similar issue, the problem was eventually
solved by adjusting my v4l brightness and contrast settings. The confusion
about comparative output quality seems to have arisen from the fact that TVs
seem to be much brighter overall, so the poor quality of the recording was
masked by the relatively dark computer CRT.

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- mdz