1

I want to convert a 1080p to 720p and also lower resolutions eventually.

I have been using ffmpeg for all my video processing activities so far, and would simply approach this task using the following command:

ffmpeg -i tos.mov -vf scale=-1:720 tos_0x720.mov

I understand that this will rescale my video to a new frame size having 720 pixels set as a fixed height and the width dynamically calculated.

What I am not sure about are the implications regarding the quality factors of the video when using ffmpeg this way.

  1. Is it valid to assume that running this command will output a perfect HD 720p quality video?
  2. What would be a benefit of using dedicated video conversion software to accomplish my goal compared to running the above command?
  • 3
    1. What do you mean by "perfect 720p quality"? 2. Why do you think that ffmpeg is not a "dedicated video conversion software"? – gronostaj Aug 12 '15 at 10:11
  • It is discouraged to crosspost the same question on multiple Stack Exchange sites. – llogan Aug 12 '15 at 15:49
11

There is no such thing as "perfect HD 720p quality video". 720p is by definition any progressive video with a height of 720 pixels. There are a million factors that affect the quality of any compressed video, far too many to detail here. In short, no, you will not get the best possible quality using the command line above. You have not considered any of the factors affecting video quality, such as bitrate, format, or profile.

ffmpeg is "dedicated video conversion software". The software you speak of often uses ffmpeg or similar underneath to do the actual work. The only advantage would be a pretty UI and easier access to settings you don't know how to use on the command line.

You may wish to start with something like the following to get an idea of what settings are available:

http://lifehacker.com/5784665/the-basics-of-video-editing-part-iv-preparing-and-encoding-your-video-for-delivery

-5

Dedicated video conversion software??? What is that? Is that something with GUI & often people pay for???

I would say that CLI is best for geeks while in GUI is for people who casually conver videos.In GUI based software you select some option & that software generate command & parameter to run free tools like that ffmpeg & x264 in background that actually converts videos.

If you re-sample video from 1080 height to 720 height,In my opinion it's still 1080p since no data is lost & you can compare captured frames in full screen of 720 height & 1080 height.See yourself.

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