As with still images, videos can be recorded in many different formats. Because videos usually contain both video and audio, they are usually stored together in a multi-media container, or wrapper, which is a file type that can hold several different types of data. There are several different (and confusing) concepts here that we need to understand.
The confusing part is that the containers are called "formats" and the type of encoding is also called a "format". A particular type of encoding is performed by a particular codec, a mathematical algorithm that does the encoding and decoding. Two of the most popular video container file types are: This means that for 640 x 480 Movie Crop Mode videos recorded in a MOV file format must be translated into an AVI file format that our planetary image processing programs can read. We cover this later in this section. Live View capture programs like Backyard EOS and EOS Camera Movie Record record AVI files, but because there are different encoding formats inside of the AVI file, not all AVI files will work in every planetary image processing program. We can usually translate a problem AVI file into one that will work with the software VirtualDub. This is covered in the next section. Compression To complicate matters even more, video and audio data can also be compressed to save space inside of an AVI or MOV file container. High-definition videos recorded in almost all consumer DSLR cameras use compression to save space. Raw file format for video is not offered. Most DSLR cameras use MOV containers with H.264/MPEG-4 Part 10 AVC video compression (it's a ridiculously complicated subject, so we might as well have ridiculously complicated names) hereafter referred to more simply as H.264. The H.264 codec does a very good job of preserving image quality while saving space. Video Codecs To access the data that is stored in a multi-media container like AVI or MOV, a codec is used. Codec is an abbreviation for compression-decompression. When the file is first written, the codec encodes the data into the file. When the file is opened, the codec decodes the data. There are hundreds of file formats and codecs. The H.264 codec is becoming a standard for recording and storing high-definition video in DSLR cameras and is also used in Blu-Ray DVD disks. Generally, you are going to need a codec on your computer to play video files. These codecs may have been installed by other programs you already have on your computer, or you may need to install them yourself. When you first copy your video files to your computer for processing, just double click on the file and see if it will play. If it does, then you have the codec you need. If it doesn't, you may need to install a codec. You can try the K-Lite codec pack, but be sure to download it from a safe location like CNET. My personal information technology specialist (my son) recommends the Combined Community Codec Pack (CCCP). Don't be put off by the communist symbol and name, it is a pun and a joke. As with ANY software that you buy or download, you should run a good virus scanner on it first before installing it. Using AVI Files If you are recording Live View with a program like Backyard EOS , or EOS Camera Movie Record, your movie will already be recorded in AVI file format. However, not all of these AVI files will work in every planetary image processing program. Here is a chart showing file types recorded with our Live View capture programs, and which of our image processing programs they will work in.
* EOS Camera Movie Record AVI video files can be re-saved as an AVI file format that AutoStakkert! and AviStack can open by using the program VirtualDub. We cover that in the next section. Transferring Movie Files to Your Computer If you have used a Live View capture program, the video files will already be written to your computer. If you have recorded 640 x 480 Movie Crop Mode, it will be recorded to the memory card in your camera. As we have seen, 640 x 480 Movie Crop Mode records MOV files that need to be translated to AVI format. Before we can perform the translation, we first have to transfer the MOV video files from the memory card in the camera to our computer. You should be fairly familiar with transferring files from your camera to your computer if you have used your camera previously for still images. There are two basic ways of transferring files from the memory card to a computer. Using MOV Video Files As noted above, most DSLR cameras shoot video movies in MOV format with H.264 compression. Unfortunately, most planetary image processing programs like RegiStax, AviStack and AutoStakkert! require uncompressed AVI video files. MOV video files will not open in these programs. Therefore, we have to convert the compressed MOV files to uncompressed AVI files. MOV to AVI Conversion Programs VirtualDub, discussed in more detail in the next section, can be used with a QuickTime converter plugin (an add-on helper) to open MOV files and easily convert them to uncompressed AVI files for use in programs like AutoStakkert!, AviStack and RegiStax. VirtualDub is the program that I recommend for converting MOV to AVI files. There are many other programs that I have tried to use to convert MOV files to uncompressed AVI files. Most of them are unsuitable for our purposes. Many of them will only produce compressed AVI files. Since the original video was already heavily compressed once when it was written as a MOV file in the camera, the last thing we want to do is re-compress it again. Canon's ZoomBrowser software that comes with Canon DSLR cameras will allow you to work with MOV files, but, again, it won't give us what we need for high-resolution planetary work. ZoomBrowser will convert the MOV to an AVI file, but it is too heavily compressed. There is no way to convert it to an uncompressed AVI file in ZoomBrowser.
Canon's ZoomBrowser will also export stills from a MOV file as JPEGs that some planetary image processing programs can work with, but these JPEGs are heavily compressed and there is no way to control the quality or amount of compression. There is a program called FFmpeg that will convert a MOV files to an AVI file, but it is a command-line program that is not easy to use if you are not familiar with command lines. There is also a WinFF, Graphical User Interface (GUI) that acts as a front end for FFmpeg that allows you to do the conversion without having to use a command line. You would think that Apple's QuickTime Pro would work the best since the MOV files are a QuickTime file format, but, alas, this is not the case. QuickTime Pro can be used to convert a MOV file to an uncompressed AVI file, but the AVI files won't open in RegiStax, AviStack or AutoStakkert!. If you want to use QuickTime Pro to do the conversion, VirtualDub is necessary to fix the AVI file. When you open the QuickTime AVI file in VirtualDub, it will say it has to reconstruct a missing index block. The error message says "index not found or damaged, reconstructing via file scan". It will then go through the entire file and fix it. Then you need to re-save the file again as an AVI out of VirtualDub. After fixing in VirtualDub, the file will open in RegiStax, AviStack or AutoStakkert! Converting MOV files to JPEGs or TIFFs In addition to AVI video files, some planetary image processing programs can also work with a series of JPEG, TIFF or BMP still image files. Remember that a video is just a series of still images. Programs like Images Plus will record video in an SID file format from which a series of uncompressed TIFF or BMP files can be extracted. VirtualDub can also extract still images from an AVI video. But since planetary image processing programs already work with AVI files, there is usually no reason to convert the AVI file to a series of stills, but it's something to keep in your toolkit. In some cases, such as with ISS solar or lunar transits, it may be useful to extract still frames from a video. File Sizes Remember that video files are just a series of still images. A 640x480 image has 307,200 pixels in it. At 8 bits, this is about a 900k file. So each frame in your video is almost a megabyte uncompressed. If you shoot 60fps, just one second of uncompressed video is almost 60 megabytes. A 1920x1080 video frame has 2,073,600 pixels in it. At 8 bits this is a 5.93 megabyte file. So each frame is almost 6 megabytes. At 30fps, one second of 1920x1080 video is about 180 megabytes. Converted uncompressed AVI files that run several minutes are going to be gigantic. That is why they are compressed in the camera. Otherwise your memory card would fill up in just a couple of minutes. The size of the MOV-compressed file saved to the memory card will depend on the length of the movie recorded and the amount of detail present in the frame. A video of Mars will not be as large as a full-frame shot of Lunar crater detail. For example, a three-minute MOV video shot at 640x480 Movie Crop Mode at 60fps contains about 10,800 frames. A three minute MOV file of Mars is about 95 megabytes. A three-minute MOV video of the lunar surface shot the same way is about 471 megabytes. Converted to an uncompressed AVI file, the original 95mb Mars 640x480 MOV video turns into a 4.7 gigabyte AVI file. The funny thing is that once you get finished with the conversion and running the video through your planetary lucky image processing program and stacking hundreds, or even thousands, of frames, the resulting single stacked frame is tiny! It will only be 640x480 pixels for Movie Crop Mode with a file size of 900k for 8 bit file and 1.8mb for a 16 bit file. As we have noted earlier in the book, having only 640x480 pixels to work with is not a problem for most planetary work. Because the planets are so small to start with, even magnified they are not larger than 640x480 pixels in most cases. Even if we could shoot video at the full resolution of the sensor, say 5184 x 3456 pixels, we would end up cropping down to just 1024x680 in Live View or 640x480 pixels in Movie Crop Mode. The original MOV fie should be archived. Even though it is compressed, it still contains the closest thing you have to raw data. And it may also contain your audio notes. Personally, I do not archive converted AVI files. They are just too big. You can always convert your original MOV file to an AVI file again if you want to reprocess it later. If you record Live View video as an AVI file, that original file should also be archived.
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