[MPlayer-users] dumpsub question

Green, Shaun Shaun.Green at msfc.nasa.gov
Thu Sep 12 18:09:02 CEST 2002


 
>Now the significative:
>i)Why do you choose keyframe=999999? Can you look for in the movie
>forward
>and back with the left-right keys? Here I use the default 250

Sure, it works great. That specification puts key frames only at scene
changes, which is where you want them. Every 250 is very wasteful and
creates too large of a file. Note: you need to specify -vc odivx however to
decode, because unfortunately the libav (ffmpeg) won't decode divx5 properly
and has color bleeding problems. -vc divx4 has problems on some multiple of
4 horizontal resolution avi's and can't decode them properly (puts white
specks all over the video). I have a short clip I could send or ftp if
anyone is interested of the ffmpeg problems.

>ii) --divx_quant ...I don't know anything about internals codecs so 
>I use the defaults

The defaults give crappy quality (in my opinion) as the range is way too
high (2,31). Specifying 2,3 produces hardly any macroblocks and so you don't
have to do postprocessing to achieve high quality playback results. It
therefore allows the playback to be much smoother with no postprocessing.

>iii) I encode audio to mp3 (brate 128). I think the quality is ok and is
>smaller than ac3 so there is more space for video.

AC3 sounds punchier, and for the average 2-3 CD rip per movie, this is not a
problem as it usually at the most 150 megs per CD. Re-encoding always loses
some data, so why not just copy it if you can. It's faster anyway.

>I had A-V sync problems a few times, and in this case all is a mess, It
>hasn't a constant delay so I can't fix it. I agree with you about
>psumode.
>If the movie has problems without it, the problems remains with the new
>core. As I said, I had A/V sync problems a few times, but if you read 
>transcode ML this seems an usual problem; I guess there is something 
>different in R1 dvds and R4 (both are ntsc) but I can prove it. 

This is because Transcode doesn't read the AC3 tracks correctly, so you have
to rip the AC3 using mplayer and read that into AVIdemux and split manually
(sucks rocks!). avisplit won't work with AC3 :o(( It actually produces new
delays and cuts off the audio before the end of each segment!

>A question: Do you watch yours movies in the monitor or in tv set?
>When I watch mines in the monitor It looks fine, with tv output I hae
>problems with the darks image, this looks some greenish

I haven't used my TV in over 3 years. TV is old technology and looks
terrible with all it's black lines etc. I use a 21 inch flat monitor to
watch them, which is BTW in effect a high definition TV, and there's NO
black lines.
 
>Go to the clip tab in dvdrip. In the FIRST clip choose your cut off
>values,
>suppose you choose top 64, bottom 64, left 4 and right 8. You only must>
>care of top and left. Bellow the image you can read the size of the
>frame
>after the clip; in this case must be 656x468, then your option is
>
>-vop crop=708:352:4:64
>
>I don't know if I can explain this, the idea is the following. From the
>upper left corner, you fix a point 4 to left, 32 to down; this point is
>the upper left corner of a rectangule 708 width and 352
>height...Anything out of it dissapears)

Thanks, I printed this and will try it tonight and let you know my results
:o)

Shaun




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