On Mon, 2 Nov 2009, Patrick O'Callaghan wrote:
> On Mon, 2009-11-02 at 19:42 -0500, Robert P. J. Day wrote:
> > On Mon, 2 Nov 2009, Patrick O'Callaghan wrote:
> >
> > > On Mon, 2009-11-02 at 13:49 -0500, Robert P. J. Day wrote:
> > > > is there a package of basic .dv video file utilities,
> > > > particularly for just *examining* the properties of a .dv
> > > > file? i've yum searched and nothing jumps out at me. i'm
> > > > just after some command-line utilities that allow me to
> > > > *inspect* the innards of various video file formats, not
> > > > necessarily do any transformations. thanks.
> > >
> > > Try tcprobe (part of the transcode package). I don't know if it
> > > handles DV but it's easy to test.
> >
> > yup, that's a start, but i'm not sure how to parse the output:
> >
> > $ tcprobe -i sample.dv
> > [tcprobe] Digital Video (NTSC)
> > [tcprobe] summary for sample.dv, (*) = not default, 0 = not detected
> > import frame size: -g 720x480 [720x576] (*)
> > aspect ratio: 4:3 (*)
> > frame rate: -f 29.970 [25.000] frc=4 (*)
> > audio track: -a 0 [0] -e 32000,16,2 [48000,16,2] -n 0x1 [0x2000] (*)
> > bitrate=1024 kbps
> > $
> >
> > i'm unfamiliar with the output format of tcprobe, so what's the
> > deal with two different frame sizes being printed? and two
> > different frame rates? how should i interpret that? thanks.
>
> Yes, I've often wondered that myself :-) The manual is silent on
> this subject. However a possible interpretation is that the
> bracketed numbers indicate defaults. Thus 720x480 is a 4x3 aspect
> ratio but the actual frame size is different so the video will be
> distorted. Transcode can crop, pad or rescale it to the correct
> ratio if required.
i suspect this is getting a bit far afield from a fedora topic, so
i'm going to look for a more appropriate forum -- a mailing list for
people interested in linux video, methinks. but just to close this
off, here's the results of my latest experimentation.
i have two .dv files i grabbed off the net, but "file" clearly sees
a difference:
$ file *.dv
pond.dv: data
sample.dv: DIF (DV) movie file (NTSC)
$
curiously, "playdv" (from the libdv-tools package) appears to play
both just fine, but tcprobe definitely sees a difference:
$ tcprobe -i sample.dv
[tcprobe] Digital Video (NTSC)
[tcprobe] summary for sample.dv, (*) = not default, 0 = not detected
import frame size: -g 720x480 [720x576] (*)
aspect ratio: 4:3 (*)
frame rate: -f 29.970 [25.000] frc=4 (*)
audio track: -a 0 [0] -e 32000,16,2 [48000,16,2] -n 0x1 [0x2000] (*)
bitrate=1024 kbps
$ tcprobe -i pond.dv
[probe_ffmpeg.c] critical: unable to open 'pond.dv' (libavformat failure)
[tcprobe] critical: failed to probe source
[rpjday@localhost dv_files]$
now i'd like to test using the "x264" utility to convert to raw
h.264 format:
$ x264 -o sample.264 sample.dv
x264 [error]: Rawyuv input requires a resolution.
$
ok, let's throw a resolution at it:
$ x264 -o sample.264 sample.dv 720x480
x264 [info]: 720x480 @ 25.00 fps
x264 [error]: no ratecontrol method specified
x264 [error]: x264_encoder_open failed
$
and, at this point, i think it's time to crack open a book on video
and get familiar so i know what the diagnostics mean. what i was
after was pulling together a collection of command-line utilities for
examining and converting video files of various formats, that's all.
apparently, i still have some research to do.
rday
--
========================================================================
Robert P. J. Day Waterloo, Ontario, CANADA
Linux Consulting, Training and Kernel Pedantry.
Web page: http://crashcourse.ca
Twitter: http://twitter.com/rpjday
========================================================================
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