MX-7x0HD HD DivX Howto
From MvixCommunity
How to convert DVD and .TS captures into High Definition and Standard Definition DivX
- A How-to-guide by dannyv45
So you have these High Definition (HD) video captures from your cable box and also have a whole bunch of DVD's sitting on your hard drive taking up all this space. I'll bet you wish you could compress or encode them to make them smaller, but still retain the same quality as the original.
Well, if that's what you're thinking, why not convert them to DivX?
Contents |
Theory of process
The key to excellent quality when converting to DivX is bitrate. The higher the bitrate the better the quality of the video. Unfortunately very high bitrates usually result in large file sizes. The key here is you need to balance between bitrate and resulting file size. The average file size of a 1 hour true High Definition 1920x1080i/p video capture is about 8GB. This would be considered our source file for the discussion below.
- For a High Definition 1280x720p end result, a bitrate around 3000bps works great and will result in a reasonable file size of approximately 1.5GB per 1 hour of High Definition video with Dolby Digital (5.1) 6 channel audio. That's almost an 8:1 compression ratio (making it 8x smaller) than the 8GB source file. The 1280x720 resolution is recommended for true High Definition captures, captured at 1920x1080i/p.
Whereas
- For a standard DVD quality 720x480 end result, a bit-rate of 1500 - 1800bps will result in a 750MB file for the same 8GB source file. Now this is almost a 16:1 compression ratio, or 16x smaller file, with DVD quality video and 6 channel audio. The 720x480 resolution is recommended for DVD rips.
Resolution, aspect ratio as well as frame rate are also key factors. The Mvix does not handle non-standard resolutions, aspect ratios or incorrect frame rates well. I will be recommending settings throughout this guide for these critical adjustments. Moving away from these suggested settings will usually result in a non-compliant encoding that generally leads to jerky/shuddering video, lock-ups and audio drop-out or synchronization problems.
For optimal audio you will want to pass-through the original captured audio, especially if it's (DD 5.1) 6 channel audio. This process does not modify the audio - it simply stream-passes the original audio unmodified thus retaining the full fidelity of the original sound track.
These processes will be covered in detail later.
Software you will need
There are several programs that can encode to DivX but this discussion will be limited to the following:
Very Important note: These programs discussed next MUST be installed in the order presented below.
Will edit the captured video and save the output as mpg. VideoReDo does 2 things besides allowing you to edit the content. It fixes any audio sync and time stamp problems which are a major problem with .ts captures and is a major reason why Dr DivX or any encoding program for that matter, will not recognize the capture as a valid stream or will result in audio/video playback issues such as audio synchronization/drop-out and video freezing. This is why VideoReDo is the most important step in this entire process. The program is not free, but not very expensive either, and is a must-have for .ts captures. VideoReDo will be discussed in more detail in the next section.
The trial version of VideoReDo will allow you to capture up to 5 minutes of video which is more than enough video to allow you to continue with this guide.
There is a free tool called MPEG StreamClip which will perform a similar function. Use of this tool is beyond the scope of this guide and will not be discussed.
- AC3filter version 1.11 (on this page 8th from the top)
You will need to install AC3filter version 1.11. Dr DivX will use it to automatically extract the (DD 5.1) 6 channel audio discussed later. To install simply click on the downloaded file and follow the prompts. At the end of the install the installer will close. There are no other adjustments to be made and the program runs transparently in the background.
Or whatever the latest package is (choose the free download, it is not necessary to purchase it or any of its plug-ins).
This is the main DivX code that Dr DivX will use to encode your video.
A very flaky program but, if you follow this guide and install the programs in the order outlined above, it should run stable and produce great results. (My encoder of choice.)
Preparing the video for Dr DivX Encode
Now that I've discussed the programs used, lets get started with actually putting together a successful Dr DivX encode.
You will first need to process the video stream using VideoRedo. This process is very fast usually taking only 6 - 7 minutes to output a compliant MPEG stream.
Press the round Open Video button.
This program will let you edit out commercials. Just load the video, edit using the slider controls and "Save as" in the MPEG format.
If you do not need to edit the video then you simply load the video into VideoReDo, press the "Save as" button and navigate to the folder you want to save the output to. VideoReDo will analyse and fix any problems it finds in the stream and output the file in a compliant MPEG format.
Regardless of whether you're editing or just converting the stream to MPEG without editing. VideoReDo does not re-encode the video it only analyses and fixes the input stream, then outputs the stream to an MPEG compliant file. The process is very fast it will process a 2 hour stream in about 6-7 minutes.
Each function button is explained in the picture below.
What to do if errors display
If you get errors such as a seeking or timing error while loading, editing or saving the original source file, it usually means there's corruption within the video stream - this is very common with captured .TS files. It is usually caused by captures that have some of the time information missing or lost/dropped frames during the capture process. This almost always leads to audio sync and frame skipping problems like jerky video. These problems are what the errors you get within VideoReDo refer to. These can be fixed with the following procedure.
Go to the "Tools" menu and select "Quick stream fix" and select the "Input stream" (your original source file); then set the "Output stream" which is the location where the new file it creates will be saved to. (If you save it to the same directory make sure you rename the file so as not to over-write the original. Refer to the picture below!)
Once the file is fixed you can reload the file into VideoReDo to do your editing. If you are not going to edit the file reload it anyway and scroll the video with the position slider from beginning to end to make sure there are no more problems. If you are not editing then there is no need to re-save the file after the "Quick stream fix" operation.
Hint: In VideoRedo cut a small sample file of about 5 minutes. This will allow you to experiment as you learn this process without having to wait hours for the encode to complete. A 5 minute sample will complete in 10 - 15 minutes.
High Definition Encode
Start Dr DivX, press the "Open" button and navigate to the folder containing the pre-processed MPG file and select it. Allow The Dr to do the first analyse process. Once this is done you will see the following:
On the "Basic" tab you will see the following selections. The recommended settings are:
- Audio tracks:
Select only the first audio track (track 1) (Mvix does not support multi-audio DivX files)
- Subtitles:
If subtitles are present select only 1 subtitle (Mvix does not support multi-sub DivX files)
- Quality = Balanced
- Profile = 1080HD
- Title= File name and location to save the DIVX encoded file to. Press the square to the right of the title field to select the save location.
Next
Click on the "Advanced" tab.
Then Click the "Pre-processing" tab:
Set the following:
- Aspect ratio = AUTO - do not check "keep pixel aspect ratio"
- Resize filter = DrFFMPEG
- Resize to width = 1280 (Height will adjust automatically keeping the proper aspect ratio)
- Quantization = H.263 optimized
Leave the rest of the settings at default
Click the "Codec" tab:
- "Rate Control" section:
- Mode = 2 pass fast
- Bitrate = 3000
- "Frame Control" section:
- Bidirectional = "Single" for a single core processor / "Multi" for a dual-core or faster processor. (This setting optimizes Dr DivX for the equipment and improves speed.)
Leave all other settings at default.
"Audio" tab:
Set the following:
- Track = Audio track 1
- Format = AC3 (This passes through the original audio which will give you DD 5.1 or DTS).
If you want to mixdown the audio to 2 channel, set the format to MP3 then select a higher bit-rate of 192 or higher and 48000khz sample rate.
My suggestion is to set it to AC3 to pass through the original audio.
Press the Encode button and the job will get added to the batch queue.
If you want to add another job then click file in the upper left-hand corner of the screen and repeat the process for the next file. When all jobs are added to the batch queue press resume.
For more detailed information on Dr DivX settings, go through the Dr DivX User Guide.
If you follow this process I think you will find it hard to distinguish the original content from the DivX encode.
I own the Mvix MX-760HD, Popcorn Hour, Buffalo Link Theatre, and a MacMini HTPC and they all have their quirks. If you stick to a DivX certified profile such as the one I have provided, you will produce media content that has the most compatibility with the vast majority of set-top media players out there.
Standard Definition Conversion settings for DVD and Standard Definition content
This process works very well for SD captures and DVD conversions. The key settings for SD are as follows:
- "Basic" tab:
- Quality = Balanced
- Profile = Home Theatre
- "Pre-processing" tab:
- Aspect ratio = AUTO - do not check "keep pixel aspect ratio"
- Resize filter = DrFFMPEG
- Resize to width = 720 (height will adjust automatically)
- Quantization = H.263 optimized
Leave the rest of the settings at default
- "Codec" Tab:
- "Rate Control" section:
- Mode = 2 pass fast
- Bitrate = 1800
- "Frame Control" section:
- Bidirectional = Single for a single-core processor / Multi for a dual-core or faster processor. (This setting optimizes Dr DivX for the equipment and improves speed.)
- "Rate Control" section:
Leave all other settings at default.
A discussion on this topic can be found here
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