I need convert to the .mp4 video with this requirements.
Container: MOV or MP4 (MPEG-4 Part 14), no edit lists, moov atom at the front of the file.
Video codec: HEVC or H264, progressive scan, closed GOP, 4:2:0 chroma subsampling.
What is means?
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If we explain everything in detail, it will result in a lengthy text, so could you tell us what exactly is unclear? I mean you can google most terms and should find a good answer about what they mean. Or is your question more about how you do that with ffmpeg?– MattApr 8, 2021 at 7:24
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Thanks for help.I need convert video file with the current requirements what I wrote. By service or ffmpeg console command it doesn't mater right now– Ivan PirusApr 8, 2021 at 9:12
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"no edit lists, moov atom at the front of the file" and "progressive scan". I dont know what it means– Ivan PirusApr 8, 2021 at 9:43
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1 Answer
Edit lists is a feature, that allows you to edit videos without re-encoding. For example, you want to remove a scene, make your edit points which are written into the container file. A video player reads those instructions and just such parts of the video. However, not many players seem to support that feature, nor does Instagram, so simply don't use it. I think it's not possible with mp4 only with mov anyway, so nothing to worry about.
The moov atom contains information how to play the video (duration, fps, etc.), it needs to be at the beginning in this case, which allows to start playing the video over the internet immediately while more data is loaded. In contrast, when the moov atom is at the file's end you need to wait until the video has been fully downloaded/buffered. The moov atom is rarely an issue in practice, most editors don't even allow to configure it and just put it at the front of the video file after the encoding is done. With ffmpeg you have control by using certain flags (I think -movflags faststart).
Progressive scan is the usual way to present a video on progressive screens (which means any screen in any modern device). There is also interlaced which is still somewhat relevant as a legacy format for TV but should always be avoided in the web. The difference is that progressive scan works with a full image per frame whereas for interlaced scan two half fields are combined into one image. Interlacing worked well on old CRT monitors, but not on modern devices. Both of these variants are often marked with a little suffix after the resolution of a video. For example you will see 1080p, referring to a video with a resolution of 1920x1080 using progressive scan, or when you see 1080i it means again a resolution of 1920x1080 but using interlacing. When creating video projects or creating a sequence where you put clips together or before export you may be asked to select profiles. Just make sure you always pick one of the progressive profiles where resolutions have the little p as suffix. Some tools may omit the distinction if they only support progressive scan.
