Guides
How to get a specific job done, what each setting actually changes, and what it costs you. Every guide ends at the tool that does the work.
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How to reduce audio file size
Four levers in order of effect, and the one that most people forget — which halves a spoken-word recording on its own.
2 min readaudioLossy vs lossless audio
What each actually does to the sound, when the difference is audible, and why converting between them in the wrong order wastes the file size you paid for.
2 min readpdfHow to reduce PDF file size
Work out what is making the file big first, then pick the method that costs you least — which is often not the compressor.
2 min readMore guides
How to convert audio without losing quality
Which conversions are genuinely lossless, which always cost something, and the one rule that prevents most avoidable damage.
2 min readaudioWhat audio format should you use?
A short answer for each common situation, and the two questions that decide it in every other case.
1 min readaudioHow audio compression works
What a psychoacoustic model actually removes, why speech and music behave so differently, and what the artefacts sound like when it goes too far.
2 min readaudioMP3 vs WAV
The size difference is about tenfold. When that trade is worth taking, when it is not, and which one to hand to someone else.
1 min readaudioWhy WAV files are so large
The exact arithmetic behind 10MB a minute, why that is the point rather than a flaw, and what to convert to when you no longer need it.
2 min readaudioMP3 bitrate explained
What each bitrate actually sounds like, the sizes they produce, and why speech and music want completely different numbers.
2 min readpdfHow to rotate PDF pages
Fixing sideways scans permanently, why your reader's rotate button is not the same thing, and why it costs nothing.
1 min readpdfHow to extract pages from a PDF
Pulling out the pages you need, why it is often better than compressing, and the privacy point people miss.
1 min readpdfHow to split a PDF
Breaking one document into several, when splitting is the right answer rather than extracting, and what each part keeps.
1 min readpdfHow to merge PDF files
Combining documents into one, why the order matters more than people expect, and what survives the merge.
1 min readpdfPDF vs JPG: which should you send?
They solve different problems. When a document should stay a document, when an image is the better answer, and how to convert either way.
2 min readpdfHow to prepare a PDF for email
The real attachment limits, and the order of operations that gets a document under them without destroying what makes it useful.
1 min readpdfHow images affect PDF file size
Why one photo can outweigh a hundred pages of text, what happens when you paste an image into a document, and how to keep a PDF small at source.
2 min readpdfWhy scanned PDFs are so large
A scan is a stack of photographs, not a document. What scanner settings actually control the size, and what you can do after the fact.
2 min readpdfHow PDF compression works
Why a PDF is large in the first place, the two very different ways of shrinking one, and the trade Dexta's compressor makes that you need to know about.
3 min readimageWhen to use JPG
Where JPG is still the right answer in 2026, the quality range that actually matters, and the two things it fundamentally cannot do.
2 min readimageWhen to use PNG
The three situations where PNG is clearly right, the one where it is clearly wrong, and why it is often the wrong default.
2 min readimageDPI vs resolution
Why DPI means nothing on a screen, when it genuinely matters, and what to check when someone asks you for a 300 DPI image.
2 min readimageHow to resize images without losing quality
Why shrinking is safe and enlarging is not, what the fit modes actually do, and the settings that keep a resized image sharp.
2 min readimageImage resolution explained
What megapixels actually buy you, how pixel dimensions drive file size, and how to work out the size an image should be.
2 min readimageJPG vs WebP
How much smaller WebP really is, what it can do that JPG cannot, and the one situation where JPG is still the right answer.
2 min readimageHow to reduce image file size
The three levers, which one to reach for first, and how far each can go before the picture starts to suffer.
2 min readimageWhat is WebP?
What WebP does differently, how well it is actually supported in 2026, when it is the right default, and the cases where it still is not.
2 min readimageJPG vs PNG: which should you use?
A short answer for the common cases, the two properties that actually decide it, and what happens when you pick wrong in each direction.
2 min readimageHow image compression works
The difference between lossy and lossless, what a JPEG actually discards, and why a screenshot and a photograph behave completely differently at the same setting.
3 min readvideoHow to prepare video for social media
The shapes each feed expects, why the aspect ratio matters far more than the resolution, and the one setting people get backwards.
1 min readvideoHow to compress video without losing too much quality
Genuinely lossless is not on offer — but the difference between a careful compression and a careless one is large, and it is mostly about order.
2 min readvideoH.264 vs H.265 vs VP9
How the three compare on efficiency and compatibility, why licensing shaped which won where, and which two Dexta can actually produce.
2 min readvideoWhy video compression takes so long
What the encoder is actually doing to every frame, why it runs on one thread here, and the things that genuinely make it faster.
2 min readvideo1080p vs 720p: which should you use?
When the difference is genuinely visible, when it is not, and why 720p is often the better delivery choice even from a 1080p source.
2 min readvideoVideo resolution explained
What the numbers mean, how pixel count drives file size, and why the resolution you record at is rarely the one you should deliver at.
2 min readvideoHow to compress a video for email
The real attachment limits, why a 24MB file can still bounce, and the settings that reliably get a phone clip under them.
2 min readvideoHow to reduce video file size
The four levers, in the order that actually saves the most, and how far to push each before it starts to show.
2 min readvideoWhy video files are so large
The arithmetic behind a 300MB phone clip, which of resolution, frame rate and duration actually dominates, and what to do about it.
2 min readvideoCRF explained
What the Constant Rate Factor actually controls, what the numbers mean, and why the same CRF gives a different result in H.264 and VP9.
2 min readvideoVideo bitrate explained
What bitrate actually measures, how it relates to file size and quality, and why Dexta gives you a quality target instead of a bitrate field.
2 min readvideoHow video compression works
Why a minute of video is not 60 still photographs, what an encoder actually throws away, and why the same setting behaves differently on two clips.
3 min read