Is 130 bad compression?
At a glance, 130 is not a standard, meaningful setting in most compression workflows. In common image and data formats, a value of 130 is typically invalid or interpreted as an extremely high ratio, and software will often reject or clamp it. The meaning and whether it’s “bad” depend on the context—whether you’re talking about image quality controls, a compression ratio, or another metric.
Interpreting 130 as an image-quality control
What the number usually means in image encoders
Many image encoders expose a "quality" parameter that controls compression strength. For JPEG, WebP, and similar formats, this quality value typically ranges from 0 to 100. Values above 100 are not standard in mainstream libraries and may cause errors or be treated as a maximum-quality setting by the encoder.
- Quality 0 yields heavy compression with obvious artifacts; 100 yields the least compression and the best fidelity. A value like 130 is outside the normal range and will usually be rejected or clamped to 100 by common tools.
- If a tool somehow accepts >100, its behavior varies by implementation; some may reinterpret the parameter as a different internal setting or simply ignore the extra portion. Always consult the specific library's documentation.
- Practically, you should choose a value within 0–100 and compare results at several increments (e.g., 60, 80, 95) rather than pushing beyond the standard range.
Conclusion: For image-quality controls, 130 is not a valid or meaningful setting in typical toolchains. When in doubt, test within the documented range and rely on objective or subjective quality assessments.
Interpreting 130 as a compression ratio or data-size metric
Understanding ratio-based or size-based interpretations
In some discussions, people refer to a compression factor or ratio like "130:1" to describe how much the data size shrank. This is a different concept from the image-quality scale and depends on the codec and content.
- For lossless data (text, executables), common practical compression ratios are modest. Ratios around 2:1 to 3:1 are common for many text corpora, with higher ratios possible in special cases, but 130:1 is extremely rare and typically indicates an unusual scenario or a highly repetitive input combined with aggressive lossy steps elsewhere.
- For lossy image or audio codecs, very high ratios can be achieved, but such extreme compression usually introduces visible degradation or audible artifacts. Whether that’s acceptable depends on the use case (preview vs archival-quality).
- Sometimes people describe “130” as a percentage, which is not a valid way to report ratio. If you’re reading a spec or a UI that uses percentages, verify what baseline the percentage refers to (original size vs post-compression size).
Conclusion: A 130:1 compression ratio is not a standard or commonly acceptable target for most content and would generally be a red flag unless the content is extremely forgiving or the goal is a very small preview.
How to judge whether your compression setting is appropriate
Beyond the numeric label, practical judgment comes from documentation, artifacts, and measurements. The steps below help determine if a given setting is suitable for your needs.
- Check the tool’s documented valid range for the parameter. If it explicitly caps at 100 (for image quality) or uses a different interpretation, follow that guidance.
- Generate sample outputs at several within-range settings and compare both file size and quality. Use objective metrics (PSNR, SSIM for images; PESQ for audio) and subjective viewing or listening tests.
- Inspect for artifacts relevant to the content type (blockiness, blurring, color shifts, ringing) and decide if they’re acceptable for your use case.
- Match the setting to your goals: quick previews, bandwidth limits, archival fidelity, or content-appropriate quality thresholds.
The takeaway is that the number 130 is not inherently "bad" by itself; its meaning and acceptability depend on context, tooling, and your quality requirements. Always verify against documentation and perform targeted testing.
Summary
130 by itself has no universal meaning in compression. In image encoding, it’s typically invalid and would be clamped or rejected; as a ratio, it signals extreme data reduction that’s rarely appropriate for most content. The right approach is to use the documented ranges, test across representative samples, and weigh size against fidelity to determine what’s acceptable for your project.
How much difference in compression is OK?
In addition, you want consistency from one reading to the next. Again, a good rule of thumb is no more than 10 percent variation between any of the cylinders. That's not to say 15 or 20 percent variation in one cylinder means your engine is junk. But a good, healthy engine should demonstrate minimal variation.
Is 130 psi good compression?
Yes, 130 psi is generally considered good compression for a gasoline engine, especially an older one, and indicates a healthy engine with good sealing. For optimal engine health, cylinder compression readings should be consistent (typically within 10% of each other) and at or above the manufacturer's minimum specification.
What 130 psi means for your engine
- Good for older engines: A reading of 130 psi is considered strong for many older stock engines and acceptable for many recreational and performance applications.
- Good sealing: At 130 psi, you can expect the engine to be running well with good piston ring and valve sealing.
- Indicates engine health: This reading suggests the engine is in good mechanical condition.
- Consistency is key: The most important factor is not just the number but how consistent the readings are between cylinders. A difference of more than 10% can point to a specific issue in the cylinder with the lower reading, such as worn piston rings or a valve problem.
What to consider for high-performance or modern engines
- For high-performance or very modern engines, 130 psi may be considered on the lower side, with ideal readings being higher.
- Always consult your vehicle's manual or a professional to find the specific compression specification for your make and model.
- A compression test is a great diagnostic tool, and consistently low or uneven readings can signal a potential problem that needs further investigation.
What is considered bad compression?
A healthy engine should have 100 PSI per cylinder. If two cylinders next to each other both have low pressure, a blown head gasket is a likely culprit. If you discover you do have low compression, the only solution is to replace the leaking part whether it's the piston, piston ring, camshaft, head gasket or valves.
Can you fix an engine with low compression?
But if you don't believe them, take it to another shop for a second opinion, but if you do have low compression, the only way to fix it is with an engine rebuild or replacement. There isn't any other way to repair the failing cylinder.
