Hi all!
      In order to decode the video stream of mp4 file,I write a h264_decoder baseed on the AOI.My config is as follow.
     In the mme_data.sql file,because I can find 0000,0000,0 in the path of  dev/io-diplay/0000,0000,0.   so  the config
 is as follow:

 --INSERT INTO outputdevices(type, permanent, name, devicepath) VALUES(1, 1, 'audiooutput', 'snd:/dev/snd/
pcmPreferredp');
INSERT INTO outputdevices(type, permanent, name, devicepath) VALUES(1, 1, 'videooutput', 'gf:0000,0000,0');
INSERT INTO zones(zoneid, name) SELECT 1, 'defaultzone';
--INSERT INTO zoneoutputs(zoneid, outputdeviceid) SELECT 1, outputdeviceid FROM outputdevices WHERE name='audiooutput';
INSERT INTO zoneoutputs(zoneid, outputdeviceid) SELECT 1, outputdeviceid FROM outputdevices WHERE name='videooutput';
INSERT INTO renderers(path) VALUES('/dev/io-media');
INSERT INTO controlcontexts(zoneid, rendid, name) VALUES( 1, 1, 'default' );
     
    In the io-media-generic.cfg file,the config is as follow:

format {
url = "*.mp4"
parser = "mp4_parser"
decoder = "h264_decoder"
}

 keepdll{
name="h264_decoder"
option=yes
}


                when I play the mp4 file, the tip is "Skipping video subgraph because there is no device specified" and 
"No video stream found.", the log is as follow.please give some advice to fix the problem,thanks very much.


mme_play(): success
io-media-generic: open('graphs/trackplayer/default')
io-media-generic/trackplayer: Calling graph create function
io-media-generic/trackplayer: Created graph instance 'default'
io-media-generic: open( 'graphs/trackplayer/default' ): success
io-media-generic/trackplayer: Calling graph handler for dcmd GRAPHOPTIONS
io-media-generic/trackplayer: Dcmd GRAPHOPTIONS returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd SETNOTIFICATION
io-media-generic/trackplayer: Dcmd SETNOTIFICATION returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd SETTRANSITION
io-media-generic/trackplayer: Dcmd SETTRANSITION returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd CAPABILITIES
io-media-generic/trackplayer: Dcmd CAPABILITIES returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd ATTACHOUTPUT
io-media-generic/mmf: writer hint snd:* found
io-media-generic/trackplayer: Dcmd ATTACHOUTPUT returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd SETVOLUME
io-media-generic/trackplayer: Dcmd SETVOLUME returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd SETSPEED
io-media-generic/trackplayer: Dcmd SETSPEED returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd GETSTATUS
io-media-generic/trackplayer: Dcmd GETSTATUS returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd SETNOTIFICATION
io-media-generic/trackplayer: Dcmd SETNOTIFICATION returning 0
io-media-generic/trackplayer: Calling graph handler for dcmd ATTACHINPUT
io-media-generic/aoi: AoHold: reloaded /fs/etfs/kscope/armle/lib/dll/mmedia/upnp_streamer.so
io-media-generic/aoi: AoRelease: unloading /fs/etfs/kscope/armle/lib/dll/mmedia/upnp_streamer.so
io-media-generic/mmf: URL '/media/drive///2009-02-12-vystava-vitejte_v_kapitalismu-360p.mp4' matches pattern '*.mp4'
io-media-generic/trackplayer: Tag 'format' has 0 kids
io-media-generic/mmf: Setting long resource 'StreamerStickyError' (value='1')
io-media-generic/mmf: Setting long resource 'MM_TMPFILE_STREAMER_SEEKABLE' (value='1')
io-media-generic/mmf: Resource 'MM_TMPFILE_STREAMER_SEEKABLE' is not supported (but optional)
io-media-generic/trackplayer: Skipping video subgraph because there is no video device specified.
io-media-generic/aoi: Couldn't negotiate formats.
io-media-generic/mmf: Configuring the queue for -1 bytes, lw = 0, hw = 0.
io-media-generic/aoi: 0:Box: "ftyp", 0...28
io-media-generic/aoi: MP4Parser: valid mp4 file.
io-media-generic/aoi: MP4Parser0 iterating through our postable event returning type...