Poor rendered MP4 quality from source MP4 footage

caspian_canuck wrote on 2/11/2018, 2:46 PM

I am not new to video editing but this problem has got me completely stumped.

My original footage is shot on Samsung Galaxy S7. MediaInfo identifies it as follows:

  • AVC
  • Profile: High@L4
  • CABAC / 1 Ref Frames, GOP: M=1 N=30
  • Resolution 1920 x 1080
  • Variable frame rate 30 fps (min: 23.089 fps, max: 30.171 fps)
  • Scan type: progressive
  • Bit rate: 17.0 Mb/s

Here's a fragment of a frame from the original footage:



I use Movie Studio HD Platinum 11.0 to edit and render the video into MP4. My project settings are:

  • Frame size: 1920 x 1080
  • Frame rate: 29.97 fps
  • Field order: None (progressive)
  • Rendering quality: Best

I have the Sony AVC/MVC codec settings configured as follows:

  • Video format: AVC
  • Frame size: 1920 x 1080
  • Frame rate: 29.97 fps
  • Field order: None (progressive)
  • Bit rate: 26 Mb/s (max available)
  • Encode mode: Automatic

The rendered MP4 video looks significantly worse than the original, with noticeable ghosting when the camera is panning or around moving objects and even static objects looking considerably softer than in the original. Here's the same fragment from the rendered file:

MediaInfo reports the following about the rendered file:

  • AVC
  • Profile: High@L4.2
  • CABAC / 2 Ref Frames, GOP: M=2 N=15
  • Resolution 1920 x 1080
  • Constant frame rate 29.97 fps
  • Scan type: progressive
  • Bit rate: 25.0 Mb/s

I suspect that the difference in CABAC settings (2 ref frames vs the original 1) is what causes the degradation in quality, but I don't know how to fix the problem.

Any thoughts or suggestions?

Comments

caspian_canuck wrote on 2/11/2018, 3:05 PM

Answering my own question:

Turns out Movie Studio by default sets up all source clips for "Smart Resample" that apparently isn't so smart after all. Once I disabled resampling (right-click on a clip > Switches > Disable Resample), the resulting video became as clear as the original. Unfortunately there doesn't seem to be a way to disable it by default for all newly imported clips, so this process has to be repeated every time for all new projects. Very annoying!

3POINT wrote on 2/11/2018, 3:13 PM

Your source has variable framerate. Your render has constant framerate. Movie Studio tries to achieve constant framerate by calculation of the missing frames through resampling. This will cause the ghosting when moving or panning. Better convert your source files to constant framerate (with Handbrake) before importing them into Moviestudio.

Musicvid wrote on 2/11/2018, 3:21 PM

If the OP is able to correct the behavior in a two generation render instead of three, I would say stick with that, or simply rewrap in ffmpeg.

rondi wrote on 2/27/2018, 4:28 PM

It would be another step--but try using Handbrake to change the rate from variable to fixed before opening it in VMS.