OBS Recording Pixelated When Moving? Fix It

You hit record, run around in the game, and the file looks perfect while you stand still. The moment you spin the camera or the screen fills with particles, the picture breaks into blocks. Then someone says “it’s your bitrate”, which is true but not very helpful.

Here is what actually happens, how to set OBS up so that motion stays clean, and what to do about recordings you already have.

Why motion makes blocks

Video compression works by sending a full picture occasionally and then sending only the changes between frames. When little changes, such as a menu screen or a person talking, the changes are small and cost few bits. When everything changes at once, such as a fast camera pan in a shooter, nearly every pixel is new, and the encoder needs a lot of data for each frame.

If the encoder has a fixed budget, it has to throw something away, so it simplifies the picture. It merges small details into blocks, which is the pixelation you see. Scenes with grass, rain, particles or smoke are the worst, because the detail is random and cannot be predicted from the previous frame. I wrote about this in why snow, confetti and grass ruin video quality, including a test where the bitrate needed for the same quality rose from 27 kbps on a flat frame to nearly 96 Mbps for heavy synthetic noise at CRF 23.

Gameplay is the extreme case. It has fast pans, sharp edges, text overlays and effects. A bitrate that looks fine for a webcam is far too low for it.

Mistake one: recording with a streaming bitrate

OBS has two jobs that share a settings page. Streaming sends video over your internet connection, so the bitrate has to fit your upload speed, commonly 4 to 8 Mbps. Recording writes to your disk, which can handle many times more.

If your recording settings use the same bitrate as your stream, the recording is as limited as the stream. People often set “Output Mode: Simple”, leave “Recording Quality” at “Same as stream”, and then wonder why their local file is blocky.

In Simple mode, change the recording quality to “High Quality, Medium File Size” or “Indistinguishable Quality, Large File Size”. The second is the right choice if you plan to edit or upload to YouTube. It makes large files, so check your disk space.

In Advanced mode, the Recording tab lets you choose its own encoder and rate control, independent of the stream.

Mistake two: choosing CBR for recording

CBR means constant bitrate. It sends the same number of bits every second regardless of difficulty, which is useful for streaming, where the connection is fixed. For recording, it is wasteful and harmful: quiet scenes use bits they do not need, and busy scenes are starved.

Use a quality-based mode instead:

• With x264, choose CRF as the rate control, with a value of about 18 to 23. Lower is better and bigger.
• With NVENC, choose CQP or the quality-based option your version offers, with a value of about 18 to 23, depending on your version and card.
• With AMD and Intel hardware encoders, use their constant quality modes where offered.

The reason is the same as in my CRF test. On a 1080p clip, going from CRF 18 to 24 reduced the file from 7,177 kB to 3,391 kB, with the PSNR dropping from 44.8 to 40.9 dB. A quality mode spreads the bits where they are needed, and a hard scene gets the extra data automatically. CRF explained covers how to choose the number.

Mistake three: a fast x264 preset

If you use the x264 software encoder, the preset decides how much CPU time the encoder spends on each frame. A faster preset makes worse decisions. In my test at CRF 23 on a 1080p clip, veryfast was more than 3 dB below medium in PSNR, and ultrafast produced a file about five times larger than medium, with a lower PSNR.

The catch with recording a game is that the CPU is busy running the game. A slower preset can cause “encoding overloaded” warnings and dropped frames. This is the reason hardware encoders exist. If x264 slower than veryfast cannot keep up on your PC, use NVENC or another hardware encoder rather than ultrafast x264.

Mistake four: scaling in the wrong place

OBS has a base (canvas) resolution and an output (scaled) resolution. If your monitor is 1440p and you output 1080p, OBS has to scale each frame. The scale filter matters: bilinear is soft, bicubic is the default, lanczos is sharper but a bit more costly. Choose lanczos if your PC can cope.

Better still, avoid scaling when you can. Record at the native resolution of the content, or set the game to the resolution you want to record. Scaling a sharp UI by a non-integer ratio is a common reason for text that looks fuzzy.

Mistake five: the wrong frame rate

Recording at 60 fps gives smoother motion, and also doubles the number of frames the encoder must handle. If your bitrate or CRF target stays the same, each frame gets fewer bits. In practice, a constant quality mode simply produces a larger file for 60 fps, which is fine. With a fixed bitrate, 60 fps looks blockier than 30 fps.

If you stream at 30 fps and record at 60, set them separately in Advanced mode, or just record at 60 and downscale for the stream.

Mistake six: a GPU that is too busy

When a game uses nearly all of the GPU, OBS may be starved for encode resources, and frames get skipped or rendered late. The video shows stutter and blocks together. OBS’s stats window shows “Skipped frames due to encoding lag” and “Missed frames due to rendering lag”. If either number is above zero, the problem is performance, not just settings.

Fixes: lower the game’s settings or frame rate cap, use a hardware encoder if x264 is overloaded, close other programs, and record to a fast drive. Setting a frame rate cap just under your monitor’s refresh rate often evens things out.

A reasonable recording setup

For Advanced output mode, recording tab:

• Type: Standard.
• Recording format: MKV (remux to MP4 afterward).
• Encoder: NVENC H.264 or HEVC if you have an NVIDIA card, otherwise x264.
• Rate control: CQP with about 20 for hardware, or CRF about 20 for x264.
• Keyframe interval: 2 seconds, or about 120 at 60 fps.
• Preset: quality or max quality for NVENC, veryfast or faster for x264 only if the CPU allows it.
• Look-ahead and psycho visual tuning: on, if your encoder offers it and your GPU can spare the power.
• B-frames: 2.

Exact option names vary between OBS versions and graphics drivers, so use the tooltips and the log. The principle is to use a quality mode and give the encoder enough room.

Why MKV is worth using

An MP4 file needs a finalizing step at the end of recording. If OBS or your PC crashes, an MP4 may have no index and cannot be opened at all. I tested this with a plain MP4 cut at 60 percent of its size: FFmpeg reported that the “moov atom” was not found, and there was nothing to play. A fragmented MP4 or MPEG-TS cut at the same point still gave me about 350 of the 600 frames, which is why the OBS community recommends MKV or fragmented formats for recording. Remux the file to MP4 afterward, from OBS’s File menu, which takes seconds and does not recompress anything. The test results are in fixing a corrupted video file.

A test that surprised me: motion alone is not the problem

I wanted to check the common claim that motion is what makes encoders fall over, so I ran a small test. I took five seconds of a 1080p, 60 fps animated clip, scaled it up to 4K, and cut two 1080p versions from it: one static crop, and one that panned sideways at about 380 pixels per second, which is a fast camera move. Then I encoded both with x264 at CRF 23, medium preset.

The static crop came out at 3,272 kB and the panning one at 3,290 kB. Essentially the same. That made sense once I thought about it: a smooth pan of a clean picture is very predictable, since every block is just last frame’s block moved a few pixels to the side. The encoder can describe that cheaply.

So what actually costs bits is not movement itself, but change the encoder cannot predict: leaves flickering in the wind, rain, particles, explosions, film grain, a camera that shakes in random directions, and scene cuts. That is why a smooth cinematic pan can look clean at a modest bitrate, while a short burst of confetti falls apart. If your recordings go blocky in specific scenes, ask what is unpredictable in them, rather than how fast things move.

I will be honest about the limits of this test. It used one clip, one kind of motion, and a clean animated source, not a gameplay capture. Real games add a mixture of effects, shaders and UI. The finding is a corrective to a simple story, not a measure of your game.

Settings for specific encoders

Names and menus change with each OBS release and driver version, so treat this as a map and not a manual.

x264 (CPU). Rate control CRF, value 18 to 23. Preset as slow as your CPU can sustain without skipped frames, which for a gaming PC is often veryfast to faster. Keyframe interval 2 seconds. Profile high. Tune none for gameplay.

NVIDIA NVENC. Recent cards have good quality encoders. Use the quality preset, a constant quality mode, look-ahead and adaptive quantization where available, and two B-frames. Record at 1080p or 1440p, whichever your content needs.

AMD and Intel. The same philosophy: quality-based rate control, the best preset the hardware can sustain, 2 second keyframes.

HEVC and AV1 recording. They give smaller files for the same quality, and are fine for recording if your editor reads them. Test your editing workflow first, since not every editor handles every codec smoothly. See H.264 versus H.265 for numbers on the efficiency difference.

If you are unsure, record a thirty second clip of your hardest scene with two or three settings and compare the file size and the look. Real footage on your own hardware tells you more than a guide.

Things that are not encoder settings

A few causes of “pixelated when moving” live outside the encoder.

The game’s own rendering. Some games use dynamic resolution or temporal upscaling, which lowers the render resolution during heavy action. The video then shows soft, blocky frames because the game rendered them that way, and no recording setting can change it.

Display capture versus game capture. Window and display capture can be slower and can drop frames. Game capture, or a dedicated capture method, is usually smoother.

Capture cards. A cheap capture card may compress the signal in hardware before OBS ever sees it, with a fixed low bitrate. If the capture card feed is blocky in the preview, the problem is in the card or its input settings.

Variable refresh rate and mismatched frame rates. A game running at 144 fps recorded at 60 fps can look uneven, which feels like poor quality.

Replay buffer settings. The replay buffer uses the recording encoder settings. If you set your recording up well but the replay clips look worse, check the replay buffer’s own configuration.

Disk space and write speed

Higher quality recordings need a fast disk. A 1080p60 recording at 40 Mbps writes about 5 MB per second, or around 18 GB per hour. A slow disk can cause stutter, which also shows up as blocks and freezes. Record to an SSD, not a nearly full drive, and keep an eye on free space. If a long session fills the disk, the recording stops with an error and you may lose the end.

What the editor and uploader do next

A clean recording can still be ruined later. If you edit, export with a high bitrate. If you upload to YouTube, remember that it compresses again, so a recording at 20 to 40 Mbps gives its encoder a much better start than 8 Mbps. YouTube video pixelated after upload covers that part.

How to judge a recording fairly

Do not judge your recording from the OBS preview or from a thumbnail in the file browser. Open the file in a player at full screen, and scrub to the hardest ten seconds you can find, such as the busiest fight or the fastest turn. Pause on a few frames and look at edges, shadows and foliage. Then check the file size. If a ten minute recording is only a few hundred megabytes, the bitrate is probably too low for 1080p gameplay. If it is several gigabytes and still blocky, look at the other causes in this article, such as the game rendering at a lower resolution or the capture source compressing the picture before OBS.

Write down the settings that gave you a good result. When OBS updates or you change your graphics card, you will have something to compare against.

Rescuing a recording that is already blocky

If you cannot re-record, a cleanup can reduce the visible blocks. Deblocking smooths block edges, denoise calms the shimmering, and a good scaler with light sharpening restores some crispness. It cannot bring back detail that the encoder discarded, and fast-motion blocks are often too severe to hide. For key clips, you can try a free preview here to see what the cleanup can do on a sample, and then decide if it is worth it.

Streams versus recordings

A recording of a stream, such as a VOD saved by a platform, is always at stream quality. If you need a high quality copy of a live event, record locally. Some creators stream at 6 Mbps and record at 30 Mbps in parallel, then use the local file for highlights. Your CPU or GPU must be able to handle two encodes, which a recent card with a dedicated encoder can do.

A quick checklist

1. Recording quality is not “Same as stream”.
2. Rate control is CRF or CQP at about 20, not CBR.
3. Encoder preset is not ultrafast.
4. The format is MKV.
5. The output resolution matches your content, scaled with lanczos if needed.
6. No skipped or missed frames in the stats window.
7. Disk space is enough for large files.

Summary

Pixelation during motion is a bitrate problem in most cases: the encoder is running out of bits exactly when the picture demands the most. In OBS, record with a quality mode, not with the stream’s CBR value, avoid ultrafast presets, record in MKV, scale carefully, and watch the frame statistics. Use a high bitrate for the recording and let the platform compress the copy it needs.