QuickTime - Why is my downloaded .AVI file not playing in QuickTime Player?
AVI stands for Audio Video Interleave. The .AVI format is what is known as a container format. It specifies a way in which a file may contain audio and video data. It does not specify how that data is encoded. The encoding of audio and video data is specified in what are known as codecs. A codec (short for COmpressor/DECompressor) tells the computer how to decode the audio and video tracks that have been encoded within the .AVI file. QuickTime Player can use numerous codecs by default. You can also add additional codecs to extend QuickTime's features using plug-ins or third-party installations.
NOTE: The information contained in this article was primarily tested and authored by Apple.
When QuickTime opens an .AVI file, it checks to see which codecs were used to encode the audio and video tracks within it. For example, an .AVI file may contain a video track encoded in the “Cinepak” codec and an audio track encoded with the “ALaw 2:1” codec. If both the audio and the video were compressed using a codec that QuickTime can use, the file will play normally. If the audio or video or both were created using codecs that QuickTime cannot use, you may see one of the following messages:
a. "QuickTime is missing the software needed to perform this operation. Unfortunately, it is not available on the QuickTime server"
b. "You may experience problems playing a video track in "filename.avi" because the required compressor could not be found."
These messages are not an indication that anything is wrong with QuickTime Player. Instead please check the list of audio and video formats included with and supported by QuickTime.
Using QuickTime Player, you may be able to determine which codec was used to compress an audio or video track:
Step 1. Open the file in QuickTime Player.
Step 2. Choose “Movie” and then select “Get Movie Properties”.
Step 3. Choose “Sound Track” or “Video Track” from the left pop-up menu in the “Properties” window.
Step 4. Choose “Format” from the right pop-up menu. The “Format” section shows the codec.
If the .AVI file is encoded using a codec that is not included with QuickTime, you might be able to find and add that codec so QuickTime can play media encoded with it. Contact the party that publishes or distributes the codec to see if a QuickTime version is available. Many third-party QuickTime components are available on the QuickTime website.