Quality Frame Rate and Buffer Length

Quality, frame rate and buffer length

ShadePlay guide › Using ShadePlay

What the quality slider does, how big clips get, which frame rate to pick, and how much memory the buffer length needs.

Quality

The Quality slider has four stops. Each is a quality level: the encoder keeps the picture at a constant quality and uses only as many bits as the picture needs, up to a peak limit. A still desktop takes very little; fast action takes up to the peak.

Slider	Name in advanced mode	Peak at 2560 × 1440, 240 fps (SDR / HDR)
Smaller files	Lite	120 / 150 Mb/s
Balanced (recommended, the default)	Default	250 / 300 Mb/s
High quality	High	400 / 500 Mb/s
Best quality	Insane	600 / 750 Mb/s

The peak grows and shrinks with your resolution and frame rate, from half to twice the numbers above: 1920 × 1080 at 60 fps gets half, 3840 × 2160 at 240 fps twice. HEVC and H.264 never go above 800 Mb/s.

Advanced mode also has a Fixed bitrate (5 to 2000 Mb/s on average, peaks up to 1.5 times that). The settings page then shows Custom (advanced settings) next to the slider. See Video settings.

How big clips get

The line under the slider says how big a minute of clip can get with your settings, for example Up to about 2.1 GB per minute of clip. (Balanced, 2560 × 1440, 240 fps, HDR, AV1, all five sound tracks). That is an upper bound, reached only with fast motion all the time; most clips are much smaller. With a fixed bitrate it is the average: About 1.1 GB per minute of clip.

Upper bounds at 2560 × 1440, 240 fps, with the default sound tracks:

Slider	SDR	HDR
Smaller files	about 870 MB	about 1.1 GB
Balanced	about 1.8 GB	about 2.1 GB
High quality	about 2.8 GB	about 3.5 GB
Best quality	about 4.2 GB	about 5.2 GB

Frame rate

Frame rate sets the frames per second in your clips: 60, 120, 144, 240 or 360 fps.

• Match your monitor, or go lower. More frames than your monitor shows add file size and nothing else. 240 fps is the default; for a 144 Hz monitor pick 144.
• Above 300 fps an NVIDIA card splits each frame between the card's video encoders (split-frame encoding) for AV1 and HEVC. H.264 can't do that and uses the encoder's fastest setting instead.
• Any other rate from 10 to 500 fps can be typed in advanced mode (Video > Frame rate > Custom…).

Buffer length

Buffer length is how much time before the key press a clip holds: 15 s, 30 s, 45 s, 1 min, 1 min 30 s, 2, 3, 4 or 5 minutes. Advanced mode also takes any number of seconds from 5 to 600.

The buffer lives in memory, never on your drive. It holds the compressed video and sound of the last minutes, plus about 8 seconds of margin, so the memory it needs is roughly the bitrate times that time:

• a quiet desktop at the default settings needs a few hundred MB;
• a minute of fast action at 2560 × 1440, 240 fps, HDR, Balanced needs about 2.5 GB;
• longer buffers and higher quality need more.

ShadePlay never uses more than a quarter of your RAM for it (at least 512 MB). When a long buffer at high quality would need more, it drops the oldest seconds instead, so clips get shorter than your buffer length. Then:

• the settings window says, for example, Your PC’s memory holds about 2 min 30 s at this quality, so clips are shorter than 5 min.;
• the tray menu shows ⚠ Clips are shorter than your buffer length – not enough memory.

To get the full length back, choose a shorter buffer or a lower quality. Changing the buffer length doesn't restart the recording.

Which settings to pick

You want	Try
Small files to share in chat apps	Smaller files, 60 fps, 30 s or 1 min
The default: sharp clips of fast games	Balanced, your monitor's refresh rate up to 240 fps, 1 min
The most detail, for editing	High quality or Best quality, your monitor's refresh rate, and enough RAM for the buffer

Changes that start a new recording

Changing the quality, frame rate, codec, HDR, 10-bit, monitor or the advanced encoder settings restarts the encoder with the new settings. ShadePlay then starts a new recording session. A clip always holds one session, never a mix of two settings, so a clip saved right after such a change is either shorter or still from before the change. Changing the buffer length or the clips folder doesn't do this.

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Next: Sound and microphone

See also: Performance and memory · Video settings · HDR clips