[Qt-interest] Practical use of Phonon in Windows

[Mike Inman]

Hi,

I have developed a (very) little Phonon app based on the mediaplayer 
demo ( http://sourceforge.net/projects/funtype/ ) - well, started 
developing is more like it, but I have achieved satisfactory performance 
working with h.264/AAC encoded .mp4 files under OS-X.  So, now I am 
trying to get something (virtually anything) working under Windows.

My app ( and the mediaplayer demo, since my app is little more than a 
re-presentation of the mediaplayer controls ) can open the demo .wmv 
files distributed with Vista, but when I try to transcode to .wmv using 
ffmpeg, I cannot find a format that Phonon will open.  I have gotten 
Windows Media Player to open some transcoded files using this ffmpeg 
command for transcoding:

---------------------

ffmpeg -i shr23.mp4 -b 1200 -vcodec wmv1 -acodec libmp3lame -ar 48000 
-ab 160k -y shr23a.wmv

FFmpeg version r11872+debian_3:0.svn20080206-12ubuntu3.1, Copyright (c) 
2000-2008 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-pp --enable-swscaler 
--enable-x11grab --prefix=/usr --enable-libgsm --enable-libtheora 
--enable-libvorbis --enable-pthreads --disable-strip --enable-libfaad 
--enable-libfaadbin --enable-liba52 --enable-liba52bin 
--enable-libdc1394 --disable-armv5te --disable-armv6 --disable-altivec 
--disable-vis --enable-shared --disable-static
  libavutil version: 49.6.0
  libavcodec version: 51.50.0
  libavformat version: 52.7.0
  libavdevice version: 52.0.0
  built on Mar 13 2009 17:48:10, gcc: 4.3.2

Seems stream 0 codec frame rate differs from container frame rate: 
48000.00 (48000/1) -> 29.97 (30000/1001)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'shr23.mp4':
  Duration: 00:03:01.2, start: 0.000000, bitrate: 1142 kb/s
    Stream #0.0(eng): Video: h264, yuv420p, 706x480 [PAR 0:1 DAR 0:1], 
29.97 tb(r)
    Stream #0.1(eng): Audio: mpeg4aac, 48000 Hz, stereo
Output #0, asf, to 'shr23a.wmv':
    Stream #0.0(eng): Video: wmv1, yuv420p, 706x480 [PAR 0:1 DAR 0:1], 
q=2-31, 1 kb/s, 29.97 tb(c)
    Stream #0.1(eng): Audio: libmp3lame, 48000 Hz, stereo, 160 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop encoding
frame= 5432 fps=126 q=31.0 Lsize=   20067kB time=181.2 bitrate= 907.0kbits/s
video:15843kB audio:3541kB global headers:0kB muxing overhead 3.523715%

----------------------------------------

The resulting .wmv file opens and plays under Windows Media Player, but 
gives Phonon Mediaplayer "Unknown error (0xc00d07e2)" when I attempt to 
open it with the phonon app on the same machine.  Google searches 
indicate a problem in the audio encoding, but aren't helpful (to me, at 
least) in resolving the problem.  Similarly, the Phonon documentation I 
have encountered is mostly along the lines of "try it, if it opens, 
great, if not, you can see where it went wrong by doing X...." which is 
better than nothing, but still not helpful in indicating what actually 
works.

So, I guess what I would really like would be some kind of list (even a 
very short one) of AV encoder types that are known to work with Phonon 
under a standard Windows XP/Vista installation - or, second best, clear 
instructions on how to beef-up the standard installation to handle some 
kind of video that I might be able to come up with via mencode/ffmpeg or 
similar transcoders.

I have also Googled some chatter about Phonon starting to graft onto VLC 
as a backend - which sounds like a very good thing to me.  Is this Linux 
only at the moment?  Is this scheduled for inclusion in Qt?

Thanks for any insight.

Mike Inman