Step 6: MeGUI: Cutting, Bitrate Calculator and AutoEncode
If you wish to cut your input so that you don't encode the entire video, it is possible to do this using MeGUI's AVS Cutter tool. To launch it, go to the "Tools" drop down menu and select "AVS Cutter". You will be asked to load in your AVS file (the one generated in Step 3) - do it.
What's going to happen here is that a list of "zones" need to be added. Each zone has a start frame and an end frame, and all frames in between will be kept (and all frames outside of the zones will be cut). You can either manually enter the desired frame number into the "Start Frame" and "End Frame" input box of the AVS Cutter tool and then press "Add" to add the zone, or use the video preview to skip to the appropriate sections and press the "Zone Start" and "Zone End" buttons to set a start/end frame, and then the "Set" button to add the zone to the list. If you specified multiple zones, you can also specify a transition between the zones (fade is the default setting). Once you are all done, press the "Add cuts to script" button and the cuts will be added to your AVS script. Press "Close" to close the "AVS Cutter" tool.
Press the "AutoEncode" button or from the "Tools" drop down menu, select "AutoEncode" to launch the Automatic Encoder setup windows.
This is pretty straight forward - just specify the output size of your video file either as a file size, or as an average bitrate and make sure the Container is set correctly, to "MP4" for the purpose of this guide. Note that certain profiles, which are based on quantizer selections, do not let you set an output file size (for the Xbox 360 or PS3 profiles, only the "2-pass" profile allows you to set the file size). For AVI/DivX/XviD conversion, you can get the same quality video at roughly 80% of the original AVI/DivX/XviD file's filesize. For 720p/1080p QuickTime HD (MOV) files, these are already using H.264 so you should try and match the file size whenever possible (again, make sure the "Average Bitrate" is under control). For maximum compatibility with the Xbox 360, the bitrate peaks should not exceed 15 Mbps (15,000 kbit/s, although I've observed brief peaks of more than 25 Mbps that seems to not cause problems, and that the Xbox 360 handled peaks better than the PS3), otherwise you could see skipped playback. There is currently no way to control the bitrate peaks for the encoded file, and so as a general rule, try to keep the average bitrate of the video under 9000 kbit/s. The output location can be changed as well - this file will be the final output file that you want, so make sure you remember where you put it and don't accidentally delete it when cleaning up (I like to put this file in a different folder to all the other files, just in case).
When you're ready, press the "Queue" button and all the necessary jobs will be added to the encoding queue.
Click on the "Queue" tab and all the jobs should be listed there. Below is an example job queue where I have two video clips "tdk" and "seu" to be encoded, an explanation of the queued jobs shown in the screenshot below:
- job1: Encoding audio track for clip "tdk"
- job2: Encoding video, 1st pass for clip "tdk"
- job3: Encoding video, 2nd pass for clip "tdk"
- job4: Muxing audio and video to MP4 for clip "tdk"
- job5: Encoding audio track for clip "seu"
- job6: Encoding video, 1st pass for clip "seu"
- job7: Encoding video, 2nd pass for clip "seu"
- job8: Muxing audio and video to MP4 for clip "seu"
New in MeGUI 0.2.6 or above is the idea of "workers". This has been introduced to take advantage of multi-core processors, allowing parallel job execution (processing more than one job at a time). Of course, certain jobs are dependent on another previous job being completed before it can begin (for example, job2-4 above requires job2-3 to be finished, and job2-5 requires all previous jobs to be finished), and so parallel execution is not always possible. But if you are encoding multiple video clips at the same time, then parallel execution allows each core of your CPU to be fully utilized at all times, allowing up to 4 video encodings at the same time on a quad core processor, for example. In essense, each "worker" represents a CPU thread that can be run on an individual core - so if you have a dual core processor, then you might want to create two workers, quad-core => 4 workers, etc. Even if you have only a single core CPU, you will still need to create at least one worker before MeGUI can start encoding video. To create a worker, from the "Worker" menu, select the "Create New Worker" option and then enter a name for this new worker.
Create as many workers as you need (again, 2 for dual-core, 4 for quad-core ...). You can right click on each job to specify which worker it will use, or you can leave it unset and MeGUI will automatically assign workers (recommended). You only need to do this the first time you use MeGUI, as worker settings are remembered.
When you are ready to start encoding, press the "Start" to start the encoding. For the above job queue example where I had two video clips "tdk" and "seu", when I press the "Start" button, both encodings will start with different workers, thus allowing me to encode two video clips at the same time (which would only be of benefit if you have multi-core or multi-CPU setups, of course). You can view the status of your workers by selecting the "Workers Summary" option from the "Workers" menu.
When it's all finished, your MP4 file should be ready. You can delete all the other files, unless you plan on making more encodings from them.