newbie-level questions on initial attempt at playing videos

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1

having finally picked up an inexpensive flat panel display, i just
took my first crack at using gstreamer to play a video or two on my
beagleboard with a moderate amount of success, but i have a few
beginner-level questions so be gentle. all i want to do is get a
couple working examples under my belt, at which point it should be
easy to take it from there.

  the display is a 1600x900 gateway flat panel.

  first, i'm using felipe contreras' prebuilt kernel and root
filesystem from here:

  Index of /~felipec/beagle-2.6.32-rc3

i dumped the kernel and rootfs onto an SD card, booted to standard
u-boot and, since i'm still not clear on various video settings,
reproduced *exactly* what's in felipe's README file, even though i'm
sure it's not entirely appropriate for my display:

setenv bootargs console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw \

  rootdelay=1 devfs=mount omapfb.mode=dvi:1024x768MR-24@60 \
  omapfb.vram=0:2M,1:4M

mmc init
fatload mmc 0 0x80300000 uImage
bootm 0x80300000

  that booted nicely, at which point i tried to play some sample
MPEG-4 files i downloaded from the net (from
http://www.yo-yo.org/mp4/, all four of them). so:

# gst-launch playbin2 uri=file://$PWD/yu.mp4
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
WARNING: from element
/GstPlayBin2:playbin20/GstURIDecodeBin:uridecodebin0: No decoder
available for type 'audio/mpeg, mpegversion=(int)4,
framed=(boolean)true, codec_data=(buffer)1510, rate=(int)11025,
channels=(int)2'.
Additional debug info:
gsturidecodebin.c(633): unknown_type_cb ():
/GstPlayBin2:playbin20/GstURIDecodeBin:uridecodebin0
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
Got EOS from element "playbin20".
Execution ended after 189315124499 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

2

Robert P. J. Day wrote:

# gst-launch playbin2 uri=file://$PWD/yu.mp4

   unsurprisingly, while the video played, it was pretty grainy and
low-quality

that video IS grainy and low quality....

3

oh, i know it's not high-quality, but the quality being displayed on
the flat panel is even *worse*, i'm guessing because i should still
adjust the kernel video settings. playing that file on my host system
thru VLC doesn't look *too* bad, the flat panel definitely looks
worse.

  and almost certainly a silly question, but how can i examine the
detailed properties of an MPEG-4 file in linux? like, say, actual
resolution? i can play any of those files in VLC, but i can't see
anywhere in VLC i can ask for the attributes of what's playing.

  as a trivial example, if i use the standard "file" command on those
files, i get nothing but:

$ file *
yu2.mp4: ISO Media, MPEG v4 system, version 2
yu3.mp4: ISO Media, MPEG v4 system, version 2
yu5.mp4: ISO Media, MPEG v4 system, version 2
yu.mp4: ISO Media, MPEG v4 system, version 2
$

i guess what i'm saying is, it's time for me to start reading up on
basic video. i'm guessing there's a package of basic MPEG-4 utilities
around somewhere.

rday

p.s. and i just lost the flat panel display again. argh.