# Bizarre - PMS transcoding **URL:** \ **Category:** Plex Media Server\ **Tags:** server-mac, apple-tv, plex-web\ **Created:** [September 28, 2020, 2:30am UTC](https://forums.plex.tv/t/bizarre-pms-transcoding/637564 "2020-09-28T02:30:16Z")\ **Posts on this page:** 1\ **Showing post:** 3
**Author:** ![Volts](https://avatars.discourse-cdn.com/v4/letter/v/a5b964/32.png) [@Volts](https://forums.plex.tv/u/Volts)\ **Post date:** [September 28, 2020, 3:45am UTC](https://forums.plex.tv/t/bizarre-pms-transcoding/637564/3 "2020-09-28T03:45:22Z")
As you’re discovering, video bitrates are hugely variable. A still scene requires almost no bits; a scene with fast action may need 10x the median. This makes the “Average Bitrate” of a file **very** misleading. Plex analyzes files to identify the moment-by-moment bitrate throughout the video. Plex also knows the buffer size of each client. It uses these together to calculate the streaming bandwidth requirements. When you look at a file’s info in Plex, `bitrate` is the file average. But if you look at the XML, `requiredBandwidths` shows how much bandwidth is needed to accommodate bitrate bursts at different buffer sizes. Before a file is analyzed, a fudge factor multiplier is used. Handbrake’s “Average Bitrate” mode controls the total file size, not moment-to-moment bitrate. A file produced with “Constant Quality” and “Average Bitrate” modes will have the same peaks and valleys in bitrate. “Average Bitrate” mode is how you create a file that’s the perfect total size for a CD or DVD, not how you target a streaming bandwidth. If you are targeting specific bandwidth, and want to pre-encode your video, one option is to use Plex’s built-in Optimizer presets. They tightly control bandwidth & required buffer sizes to maximize video quality for specific bandwidth settings. If you want to encode for specific streaming bandwidth yourself, there’s an exhaustive thread about it here: > [@\[How To\] Pre-encode to avoid Transcoding (using VidCoder Presets)](https://forums.plex.tv/t/how-to-pre-encode-to-avoid-transcoding-using-vidcoder-presets/573857): > > Hi all, [Downmix your Surround Sound to Stereo before using this “Pre-encoding” guide](https://forums.plex.tv/t/how-to-downmix-surround-sound-to-aac-stereo-properly-using-ffmpeg-batch-converter/575073) I have decided to make available my x264 presets for VidCoder that have taken me so long to come up with, but which will 99.9% do away with all your transcoding issues slight_smile There are many Handbrake/VidCoder presets and settings sprinkled throughout the Plex forums and the internet for that matter. What makes these presets different? Why would I not just use the normal encoder “Preset” and “Tune… --- _[View the full topic](https://forums.plex.tv/t/bizarre-pms-transcoding/637564)._