• Adobe Premiere Pro

  H264 Artifacts With Fades in Premiere Pro CS6 for Low Bitrates

  Posted by Jacob Geoff on June 19, 2013 at 8:53 pm

  I’m working with class lectures and have added a fade-in transition at the beginning. Things look great when I’m editing in Premiere Pro CS6, but on export, the fades look terrible. Here’s a snap during mid fade.

  

  If you’d like to see the actual footage, here’s a short clip (1Mb). The settings I used for exporting are below

  Format: H.264 (exporting as MP4, not QuickTime mov)
  Size: 1920 x 1080
  Profile: Baseline
  Level: 4.0
  Bitrate Encoding: VBR, 2 Pass
  Target Bitrate (Mbps): 0.8
  Maximum Bitrate (Mbps): 1.0
  Key Frame Distance: 300
  Use Previews Unchecked
  Use Frame Blending Unchecked
  Multiplexer: MP4
  Stream Compatibility: iPod

  Here’s what I’ve tried without any luck.
  – Changed cross dissolve from 1/2 second to 2 seconds
  – Updated Adobe Media Encoder CS6 to 6.0.2.81, the latest version
  – Tried Checking “Render at Maximum Depth” and “Use Maximum Render Quality” individually and together
  – Tried Key Frame Distances of 72, 90, 150, and 300

  What did make a difference was upping the bitrate. Here’s a clip with target bitrate 2.0 Mbps and max bitrate 2.4 Mbps, but things are still blocky. Doubling this for a target bitrate of 4.0 and max bitrate of 4.4 removed the artifacts from the fade, but the rest of the video looks the same so it seems wasteful – especially as I have to stream these hour long lectures so smaller file size is critical (hence the 0.8 – 1.0 bitrate choice).

  Is there a setting that I am missing or something else than upping the bitrate that I can try to resolve the fade issue?

  Cheers,
  Jacob

  Jacob Geoff replied 13 years, 2 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Ivan Myles

  June 20, 2013 at 2:06 am

  800kbps is very low for 1080p. It probably works for lecture notes because there isn’t much change from frame to frame, but blocking occurs during the transition because there isn’t enough bandwidth to handle all the changes. Here are a few alternatives:

  – Keep average bitrate low but increase the maximum bitrate; this will potentially provide headroom for the transitions
  – Use a wipe or slide transition instead of fade so that only part of the image changes at a given time
  – Do not use a transition; just cut to black (or white, or a new title); this alternative will likely produce the best results

  A few notes about your other settings:

  – Render at Maximum Bit Depth matters if processing and exporting at 10+ bits per channel; you can leave it unchecked for H.264
  – Maximum Render Quality is intended for use when exporting at smaller dimensions than the sequence
  – Changing Stream Compatibility to Standard and Profile to Main or High will provide better compression via CABAC encoding; however, the compressed file might not play on some devices (Main Profile will be more compatible than High)
  – Consider publishing low-bitrate versions at lower resolution (1280×720 or even 854×480) and encode 1080p at higher bitrate; similarly, retangular pixels (1440×1080) can help, but the video won’t play correctly in many media players
• 

  Jacob Geoff

  June 20, 2013 at 8:06 pm

  Hi Ivan,

  Setting the Max Bitrate up took care of the fade issue while keeping the file size small. And your breakdown of the other settings was particularly helpful for some other videos I had laying around.

  Cheers!
  Jacob

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