This tool improves the video qualitity by changing the quantization parameter (QP) within a frame. Considerations for Decoding and Encoding 4K Streams.Using FFmpeg for Video Encoding and Decoding.If blocky artifacts persist even with these settings, reduce the -g parameter until they are gone. Meaning that the encoder is allowed to put subsequent keyframes next to one another, and must put at least one keyframe every thirty frames. -keyint_min 1 -g 30 sets the minimum distance between any two keyframe is set to 1, and the maximum to 30.-sc_threshold 99 sets the "scene cut" threshold to 99, meaning that if 1% of the frame is different enough, it will be considered a different "scene" which needs to be cut to via inserting a new key frame.Once the asset is timed and placed in Unity and you don't need to scrub the timeline, replace the proxy version with this full-resolution asset for the final build. Full-Resolution Final Asset - Encode this at the final resolution, with only enough I-Frames to avoid artifacts.Low-Resolution 'Proxy' - Encode this with an I-Frame every frame, but smaller dimensions for a working asset that scrubs quickly to speed up the placement and timing of the asset in Unity.Making each frame into an I-Frame dramatically increases the file size, so we recommend encoding multiple versions of your asset: Add I-Frames to every frame by adding -g 1 to the FFmpeg command. By default FFmpeg places them at most 250 frames apart, which leaves large gaps on the timeline where the player doesn't have a complete frame to reference. Quickly scrubbing H.264 videos requires frequent I-Frames, which are useful when setting reconstruction settings or blocking. Optimizing for scrubbing in Unity & Proxy workflow If you have calculated the height automatically, verify the video resolution by right clicking the video file, selecting properties, and viewing the frame height/width under Details. To edit these values, open the metadata file which was exported with the Image Sequence in a text editor and scroll to the very bottom of the file.Įdit the textureHeight and textureWidth to match the resolution of your re-encoded clip. When resizing a Depthkit clip, you must also edit your metadata file to reflect this change in resolution. setsar=1:1 forces a pixel aspect ratio of 1:1 which, when scaling, is necessary to ensure the best performance in Unity.The image aspect ratio doesn't need to be maintained, so this command scales the width and height independently to fit within your desired target resolution. -vf scale='min(4096,iw)':'min(ih,4096)' (video filters) - scale the video to maximum width of 4096, a maximum height of 4096.In the example below, we are downscaling to 4096 to fit within hardware NVDEC resolution limitations, but you may need to specify a lower maximum resolution, such as 2048 for mobile. You may need to downscale your Combined Per Pixel video files due to hardware decoding resolution limitations on your computer or target device.
See this documentation from Oculus for further information.ĭownscaling your Combined Per Pixel video files Keep this value at or under 511 to stay within spec.
-x264-params mvrange=511 - For H.264 videos, this prevents artifacts generated when the motion vector range (mvrange) exceeds the H.264 level 5.2 specification.-pix_fmt yuv420p - applies the YUV 4:2:0 pixel format, which reduces file size.We recommend 15 for a high quality asset, but dialing this down will reduce file size if needed. It ranges from 0–51 (0 is lossless and 51 is heavily compressed) with a default of 23. Using constant bitrate with -crf 15 (constant rate factor)Īn alternative to encoding a variable bitrate with -b:v (x)M is to use a constant bitrate with -crf 15 (constant rate factor), which targets uniform quality across the clip. You can adjust this based on your preference to balance file size and quality. -b:v 5M (bitrate) - encode with a target bitrate of 5 Mbps.This can be changed to other codecs like libx265 (H.265/HEVC) codec depending on your target publishing platform. -c:v libx264 (codec) - encodes using the libx264 (H.264) codec.
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