More tools to transcode videos.
Hi, I'm Lisa Melton. I created these tools to transcode my collection of Blu-ray Discs and DVDs into a smaller, more portable format while remaining high enough quality to be mistaken for the originals.
Unlike my Other Video Transcoding project, these tools are just separate standalone scripts which must be installed and updated manually.
You do know how to install a Ruby script manually, right? As well as HandBrakeCLI and ffprobe? Because both of those tools are required by my scripts.
Currently, this project contains four video transcoding tools:
two-pass-transcode.rbhevc-transcode.rbnvenc-hevc-transcode.rbav1-transcode.rb
About 90% of the code in each script is the same. Really. Carefully and inefficiently duplicated. By design. Why? Because it's unlikely you'll ever use more than two of these. In fact, I expect most people will use only one.
This Is The Way™. At least the best way I've found to create high-quality 1080p and smaller-resolution videos. This uses the venerable x264 software-based encoder. With two-pass ratecontrol, it is a bit slower than other x264-based systems but the output quality is worth the wait, as is the output size. All audio is in AAC format to further reduce output size.
Video:
| Resolution | H.264 bitrate |
|---|---|
| 1080p (Blu-ray) | 5000 Kbps |
| 720p | 2500 Kbps |
| 480p (DVD) | 1250 Kbps |
Audio:
| Channels | AAC bitrate |
|---|---|
| Surround | 384 Kbps |
| Stereo | 128 Kbps |
| Mono | 80 Kbps |
For this script only, 4K inputs are automatically scaled to 1080p and HDR is automatically converted to SDR color space.
Video is also automatically cropped and forced subtitles are automatically burned into the video track.
But there are many customization options including direct access to most of the HandBrakeCLI API.
Designed for 4K HDR content, this script uses the x265_10bit software-based encoder with a constant quality ratecontrol system. But it's reeeeeally slow. I mean, really slow. However, it does produce high-quality output. You just have to decide whether it's worth it.
One big selling point is that the x265_10bit encoder can produce output compatible with both the HDR10 and HDR10+ standards as well as Dolby Vision.
Audio and subtitle track behavior is the same as with two-pass-transcode.rb.
Warning
Recent changes to Nvidia drivers, versions 555.85 and later, have a bug (or feature?) which ignores target bitrates for HEVC output so that only constant quality values are honored. Until this is fixed, don't use the --bitrate option with the nvenc-hevc-transcode.rb script because the encoder will ignore it and do something undefined.
Also designed for 4K HDR content, this script uses the nvenc_h265_10bit Nvidia hardware-based encoder, also with a constant quality ratecontrol system, because you can't always afford to wait on x265_10bit. The output will be slightly larger and somewhat lesser in quality but you'll get it a LOT faster. A lot.
But be aware that the nvenc_h265_10bit encoder can only produce HDR10-compatible output.
Audio and subtitle track behavior is also the same as with two-pass-transcode.rb.
This Is The Future. Unfortunately, the AV1 video format is currently the Star Trek Future. Other than desktop PCs, most devices can't play it yet. This script uses the svt_av1_10bit software-based encoder with a constant quality ratecontrol system. Although the encoder is already quite good, it's still a work in progress. And while the encoder is slower than x265_10bit on ARM platforms, it's faster on Intel and usually produces smaller output. So it's certainly worth a try. Especially on 4K HDR content.
The svt_av1_10bit encoder can produce output compatible with the HDR10 and HDR10+ standards, but not Dolby Vision.
While audio and subtitle track behavior is similar to the other scripts, audio is in Opus format at slightly lower bitrates. Why Opus? Because if you can play AV1 format video, you can certainly play Opus format audio.
Did you actually read the --help option output for each script? Go ahead. I'll wait.
See? Aaaaand... that's how you use them.
Please report bugs or ask questions by creating a new issue on GitHub. I always try to respond quickly but sometimes it may take as long as 24 hours.
This project would not be possible without my collaborators on the Video Transcoding Slack who spend countless hours reviewing, testing, documenting and supporting this software.
More Video Transcoding is copyright Lisa Melton and available under a MIT license.