Transcoding Synology/Serviio

Hi tried asking about this on the Synology forum but perhaps it is an error more familiar to Subsonic community. I have used Subsonic on PC since forever but now very excited to have it on the NAS.
Problem is ffmpeg/permissions problem
Everything seemed to work ok but then I had to reboot, reinstall this and some associated packages etc..
I have maintained the Serviio Synology package installed (but stopped) in order to (as I understand it) allow this Subsonic install to use some ffmpeg Serviio enhancements.
Now my usr/syno/synoman/webman/3rdparty/subsonic/subsonic.log is full of entries like the following, every time the media scanner encounters anything that's not a normal mp3 (e.g. a FLAC, mpeg etc.)
I can't, at least not in the normal Synology DSM OS GUI interface, give the "subsonic" user access to this particular folder, because it isn't a folder listed there. But I can go into it with root privilges and change. But I don't know what I would change permissions to, I do not understand the unix permissions "numbers" etc. Tips much appreciated
[2017-03-17 03:01:53,817] WARN FFmpegParser - Error when parsing metadata in /volume1/music/[filename.mp4]
java.io.IOException: Cannot run program "/usr/syno/synoman/webman/3rdparty/subsonic/transcode/ffmpeg": error=13, Permission denied
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
at java.lang.Runtime.exec(Runtime.java:620)
at java.lang.Runtime.exec(Runtime.java:485)
at net.sourceforge.subsonic.service.metadata.FFmpegParser.getRawMetaData(FFmpegParser.java:69)
at net.sourceforge.subsonic.service.metadata.MetaDataParser.getMetaData(MetaDataParser.java:47)
at net.sourceforge.subsonic.service.MediaFileService.createMediaFile(MediaFileService.java:483)
at net.sourceforge.subsonic.service.MediaFileService.updateChildren(MediaFileService.java:403)
at net.sourceforge.subsonic.service.MediaFileService.getChildrenOf(MediaFileService.java:201)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:235)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:239)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:239)
at net.sourceforge.subsonic.service.MediaScannerService.doScanLibrary(MediaScannerService.java:177)
at net.sourceforge.subsonic.service.MediaScannerService.access$000(MediaScannerService.java:48)
at net.sourceforge.subsonic.service.MediaScannerService$2.run(MediaScannerService.java:147)
Caused by: java.io.IOException: error=13, Permission denied
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:247)
at java.lang.ProcessImpl.start(ProcessImpl.java:134)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
... 13 more
[2017-03-17 03:01:56,771] INFO MediaScannerService - Scanned media library with 14750 entries.
Thank you for any help
Cheers
Problem is ffmpeg/permissions problem
Everything seemed to work ok but then I had to reboot, reinstall this and some associated packages etc..
I have maintained the Serviio Synology package installed (but stopped) in order to (as I understand it) allow this Subsonic install to use some ffmpeg Serviio enhancements.
Now my usr/syno/synoman/webman/3rdparty/subsonic/subsonic.log is full of entries like the following, every time the media scanner encounters anything that's not a normal mp3 (e.g. a FLAC, mpeg etc.)
I can't, at least not in the normal Synology DSM OS GUI interface, give the "subsonic" user access to this particular folder, because it isn't a folder listed there. But I can go into it with root privilges and change. But I don't know what I would change permissions to, I do not understand the unix permissions "numbers" etc. Tips much appreciated

[2017-03-17 03:01:53,817] WARN FFmpegParser - Error when parsing metadata in /volume1/music/[filename.mp4]
java.io.IOException: Cannot run program "/usr/syno/synoman/webman/3rdparty/subsonic/transcode/ffmpeg": error=13, Permission denied
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
at java.lang.Runtime.exec(Runtime.java:620)
at java.lang.Runtime.exec(Runtime.java:485)
at net.sourceforge.subsonic.service.metadata.FFmpegParser.getRawMetaData(FFmpegParser.java:69)
at net.sourceforge.subsonic.service.metadata.MetaDataParser.getMetaData(MetaDataParser.java:47)
at net.sourceforge.subsonic.service.MediaFileService.createMediaFile(MediaFileService.java:483)
at net.sourceforge.subsonic.service.MediaFileService.updateChildren(MediaFileService.java:403)
at net.sourceforge.subsonic.service.MediaFileService.getChildrenOf(MediaFileService.java:201)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:235)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:239)
at net.sourceforge.subsonic.service.MediaScannerService.scanFile(MediaScannerService.java:239)
at net.sourceforge.subsonic.service.MediaScannerService.doScanLibrary(MediaScannerService.java:177)
at net.sourceforge.subsonic.service.MediaScannerService.access$000(MediaScannerService.java:48)
at net.sourceforge.subsonic.service.MediaScannerService$2.run(MediaScannerService.java:147)
Caused by: java.io.IOException: error=13, Permission denied
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:247)
at java.lang.ProcessImpl.start(ProcessImpl.java:134)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
... 13 more
[2017-03-17 03:01:56,771] INFO MediaScannerService - Scanned media library with 14750 entries.
Thank you for any help
Cheers