On 20 Aug 2003, Florin Andrei wrote:
> BTW, here's what happened when i extracted the fields:
>
> [EMAIL PROTECTED] work]$ lav2yuv -f 10 yose.avi | y4mtoppm | pnmsplit -
> pnm/image%d.pnm
> pnmsplit: WRITING pnm/image0.pnm
An easier (I think) way of checking out the YUV4MPEG2 parameters
is with the 'head' command.
lav2yuv -f 10 yose.avi | head -1
will give something like this:
YUV4MPEG2 W720 H480 F30000:1001 Ib A10:11
The tag 'Ib' means bottom field first.
>
> That confirms my feeling that it's a bottom-first stream.
The data came from a DV capture? If so then is will *always*
be bottom field first - that's the DV standarad and no other
order is ever used.
> I took only the first AVI file in the DV directory, which has approx 2
> minutes worth of video (out of the total of 60 minutes).
I was going to suggest that yesterday but figured you'd think of
it yourself :)
> I created three different DVDs:
> - default field order settings (no -z)
> - using -z t
> - using -z b
> I then created three different SVCDs:
> - default field order settings (no -z)
> - using -z t
> - using -z b
>
> I then went to a local computer/hardware store and pretended i was
> choosing a DVD player by testing it with "home-made DVDs". :-) I think i
Good Idea - I was about to do a similar thing when looking for
a player that would handle the rewriteable DVD media. Fortunately
I got lucky with the Philips unit ;)
> The results were identical no matter which DVD player, no matter whether
> it was DVD or SVCD:
> - all disks created with "-z b" were perfect
> - all other disks experienced juddering
>
> Obviously, something changed since last summer. But what?
Something in the pipeline you're using is inverting the field
order.
TO find out which tool is doing it use the 'head' command as
shown above. Start with just the 'lav2yuv | head -1' as shown,
then add one more tool, "lav2yuv | next_tool | head -1' and look
at the 'I' tag. Keep going until all tools have been added.
IF this is a DV file then you'll get better quality by using the
smilutils and making sure that they are built using FFMPEG's
libavcodec. Ffmpeg has a better DV decoder from what I and a
couple other folks have seen.
Good Luck tracking down where things are going awry.
Steven Schultz
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