Transcode a Makemkv .mkv using ffmpeg?

Hi all,
I'd like to start ripping/backing-up my DVD/Blu-ray library to my Serviio server.
So far, I've ripped a lossless .mkv using Makemkv from a BD as this seems to be the easiest (and free) method. If my understanding is correct, I can use ffmpeg to transcode this .mkv into a smaller .mkv as the files are huge. I'm happy to accept reduced resolution and audio quality for the sake of of smaller files.
I've looked at Handbrake, but I've read it's built on a very old version of x264 and also I dont understand all of the options. I'd like to keep things simple and use ffmpeg, ideally using a .bat file that simplifies the transcoding to a drag and drop procedure.
I'd be grateful if some one could help me with the correct command line to create an output .mkv that meets the following spec:
Video: AVC 720p High@L4.1 (with ref. frames 4 or less to play on a PS3)
Audio: AC-3 6 channel (5.1) CBR (can anyone tell me why audio always seems to be 384kbps?) + forced English subtitles, if at all possible.
If I'm going about this all wrong, I'd appreciate any feedback and advice. I have read about other methods that involves ripping then encoding video and audio separately then muxing into a container, but this all seems quite convoluted and I'm hoping what I'm trying to achieve with Makemkv and ffmpeg will keep the process fairly simple without significantly impacting on quality.
Thanks for your help.
I'd like to start ripping/backing-up my DVD/Blu-ray library to my Serviio server.
So far, I've ripped a lossless .mkv using Makemkv from a BD as this seems to be the easiest (and free) method. If my understanding is correct, I can use ffmpeg to transcode this .mkv into a smaller .mkv as the files are huge. I'm happy to accept reduced resolution and audio quality for the sake of of smaller files.
I've looked at Handbrake, but I've read it's built on a very old version of x264 and also I dont understand all of the options. I'd like to keep things simple and use ffmpeg, ideally using a .bat file that simplifies the transcoding to a drag and drop procedure.
I'd be grateful if some one could help me with the correct command line to create an output .mkv that meets the following spec:
Video: AVC 720p High@L4.1 (with ref. frames 4 or less to play on a PS3)
Audio: AC-3 6 channel (5.1) CBR (can anyone tell me why audio always seems to be 384kbps?) + forced English subtitles, if at all possible.
If I'm going about this all wrong, I'd appreciate any feedback and advice. I have read about other methods that involves ripping then encoding video and audio separately then muxing into a container, but this all seems quite convoluted and I'm hoping what I'm trying to achieve with Makemkv and ffmpeg will keep the process fairly simple without significantly impacting on quality.
Thanks for your help.