[FFmpeg-user] Quicktime DV MOVs - 2 different SAR informations
phil_rhodes at rocketmail.com
Mon May 12 20:48:23 CEST 2014
The codec that is used in DV movies includes the pixel aspect ratio in each frame.
Many containers (such as AVI and Quicktime) either contain, or can contain, pixel aspect ratio.
Obviously this can cause problems because it's possible for them to be set differently. In this case, I'd ordinarily believe the one in the codec, as it's likely to have been set by the recording device, which is often a camera, and which will therefore know what it should be doing. It's not entirely reliable as of course miniDV and DVCAM decks can be used to record analogue inputs with incorrect settings, but it's probably more reliable than the container's information in most cases.
Many applications don't know how to read the information in the individual codec frames; presumably the DV decoder in ffmpeg does, but this is all a guess based on that.
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