--- title: What Is Video Compression? How Codecs Shrink Video description: What is video compression? Learn how a video compression codec shrinks files while preserving quality for faster streaming and storage. image: https://blog.blazingcdn.com/hubfs/Gemini-Blog/image-Oct-06-2026-07-30-20-2950-AM.jpeg --- [![BlazingCDN](https://blog.blazingcdn.com/hubfs/Logo/blog-logo-w.png)](https://blog.blazingcdn.com?hsLang=en-us) [๐Ÿ“˜Learn โ–พ](https://blog.blazingcdn.com/cdn-learn?hsLang=en-us) [CDN Fundamentals](https://blog.blazingcdn.com/cdn-fundamentals?hsLang=en-us) [By Content Type](https://blog.blazingcdn.com/by-content-type?hsLang=en-us) [Advanced Concepts](https://blog.blazingcdn.com/advanced-concepts?hsLang=en-us) [Glossary](https://blog.blazingcdn.com/glossary?hsLang=en-us) [โšก Web Performance](https://blog.blazingcdn.com/web-performance?hsLang=en-us) [๐ŸŽฌVideo & Streaming โ–พ](https://blog.blazingcdn.com/video-streaming-cdn?hsLang=en-us) [๐Ÿ”ด Live Streaming](https://blog.blazingcdn.com/live-streaming?hsLang=en-us) [๐Ÿ“บ VOD & OTT](https://blog.blazingcdn.com/vod-ott?hsLang=en-us) [๐Ÿ’ฐ Bandwidth & Costs](https://blog.blazingcdn.com/bandwidth-costs?hsLang=en-us) [๐Ÿญ Other Industries โ–พ](https://blog.blazingcdn.com/cdn-industry-insights?hsLang=en-us) [๐Ÿ“บ Media & Broadcasting](https://blog.blazingcdn.com/media-broadcasting?hsLang=en-us) [๐Ÿ’พ Software & SaaS](https://blog.blazingcdn.com/software-saas?hsLang=en-us) [๐Ÿ—๏ธ DevOps & Cloud Infra](https://blog.blazingcdn.com/devops-cloud-infra?hsLang=en-us) [๐Ÿ“š AdTech & Advertising](https://blog.blazingcdn.com/adtech-advertising?hsLang=en-us) [๐ŸŽฎ Gaming & Esports](https://blog.blazingcdn.com/gaming-esports?hsLang=en-us) [๐Ÿ“ฑ Mobile Apps & Developers](https://blog.blazingcdn.com/mobile-apps-developers?hsLang=en-us) [๐Ÿค– AI & Machine Learning](https://blog.blazingcdn.com/ai-machine-learning?hsLang=en-us) [๐Ÿ›๏ธ Enterprise & Corporate](https://blog.blazingcdn.com/enterprise-corporate?hsLang=en-us) [๐Ÿ“š E-Learning & EdTech](https://blog.blazingcdn.com/e-learning-edtech?hsLang=en-us) [๐ŸŸ๏ธ Sports & Live Events](https://blog.blazingcdn.com/sports-live-events?hsLang=en-us) [๐Ÿ’ฐ Pricing & Costs โ–พ](https://blog.blazingcdn.com/cdn-pricing-and-cdn-costs?hsLang=en-us) [Provider Pricing](https://blog.blazingcdn.com/provider-pricing?hsLang=en-us) [Cost Optimization](https://blog.blazingcdn.com/cost-optimization?hsLang=en-us) [Decision Support](https://blog.blazingcdn.com/decision-support?hsLang=en-us) [โšกCompare โ–พ](https://blog.blazingcdn.com/cdn-comparison?hsLang=en-us) [Provider Comparisons](https://blog.blazingcdn.com/provider-comparisons?hsLang=en-us) [Strategy Comparisons](https://blog.blazingcdn.com/strategy-comparisons?hsLang=en-us) [Ratings & Benchmarks](https://blog.blazingcdn.com/cdn-ratings-and-benchmarks?hsLang=en-us) [๐Ÿ“Š Benchmarks](https://blog.blazingcdn.com/cdn-ratings-and-benchmarks?hsLang=en-us) [๐Ÿ”’ Security โ–พ](https://blog.blazingcdn.com/cdn-security?hsLang=en-us) [Attack Protection](https://blog.blazingcdn.com/attack-protection?hsLang=en-us) [Encryption & Access](https://blog.blazingcdn.com/encryption-access?hsLang=en-us) [Video & DRM Security](https://blog.blazingcdn.com/video-drm-security?hsLang=en-us) [๐Ÿ“ Case Studies](https://blog.blazingcdn.com/case-studies?hsLang=en-us) [๐Ÿ”Œ Integrations](https://blog.blazingcdn.com/integrations?hsLang=en-us) [๐Ÿ› ๏ธ Tools](https://blog.blazingcdn.com/cdn-tools?hsLang=en-us) [Get Started](https://blazingcdn.com/sign-up-contact-form/) [Learn](https://blog.blazingcdn.com/en-us/tag/learn) [Video - Video & Streaming](https://blog.blazingcdn.com/en-us/tag/video-video-streaming) [Video - Bandwidth & Costs](https://blog.blazingcdn.com/en-us/tag/video-bandwidth-costs) [Learn - CDN Fundamentals](https://blog.blazingcdn.com/en-us/tag/learn-cdn-fundamentals) # What Is Video Compression? How Codecs Shrink Video BlazingCDN Oct 6, 2026, 9:32:08โ€ฏAM ![](https://blog.blazingcdn.com/hubfs/Gemini-Blog/image-Oct-06-2026-07-30-20-2950-AM.jpeg) Video compression is the process of encoding moving images into far fewer bits by removing spatial redundancy inside each frame, temporal redundancy between frames, and detail the human visual system barely notices. A video compression codec such as H.264, HEVC or AV1 typically shrinks raw 1080p video by 150 to 400 times before it is streamed. Uncompressed 1080p video at 30 frames per second with 8-bit 4:2:0 sampling runs at about 746 Mb/s. As of 2026, H.264 streams typically deliver that picture at 4 to 6 Mb/s, and AV1 reaches comparable perceived quality at roughly 2 to 3 Mb/s. Codec choice therefore sets the floor of every video delivery bill. ## **How video compression works inside a codec** Every mainstream codec since MPEG-2 uses the same hybrid block-based design: predict each block of pixels, subtract the prediction, transform the leftover error, quantize it, then entropy-code the result. The codecs differ in block sizes, prediction modes and entropy coders. They do not differ in this basic pipeline. ### Intra frames: compressing a single picture An intra frame (I-frame) is coded using only its own pixels. The encoder predicts each block from already-decoded neighbors (H.264 has 9 directional modes for 4x4 luma blocks, HEVC has 35, AV1 has 56 plus specialized tools). It then runs a DCT-like transform on the residual, discards high-frequency coefficients through quantization, and packs the rest with CABAC or an equivalent arithmetic coder. An IDR frame is an I-frame that also resets reference buffers, so a decoder can start cleanly from it. ### Inter frames: exploiting time Predicted frames (P) and bi-directional frames (B) reference other decoded frames. The encoder searches for each block's best match elsewhere, sends a motion vector plus a small residual, and often skips the residual entirely for static areas. Inter frames commonly cost 5 to 20 times fewer bits than an I-frame of the same scene, which is where most of the 150x to 400x ratio comes from. ### The GOP and why it matters for delivery The group of pictures (GOP) is the run of frames between two I-frames. Long GOPs compress better; short GOPs give faster seeking and channel start. For HLS and DASH, each segment must begin on an IDR frame, so a 2-second GOP at 24 fps (48 frames) is a common choice that lines up with 2-, 4- or 6-second segments. ## **Lossy vs lossless video compression** Lossless video compression reconstructs every pixel exactly and usually achieves only 2:1 to 3:1 on camera footage. Lossy compression discards information the viewer is unlikely to notice and reaches 100:1 or more. Streaming uses lossy codecs almost exclusively; lossless and visually lossless formats live in capture, editing and archive mezzanine files. The loss happens in two places: chroma subsampling (4:2:0 stores color at a quarter of luma resolution) and quantization. The quantization parameter (QP) controls how coarsely transform coefficients are rounded. In H.264 and HEVC, raising QP by 6 roughly halves the bitrate and visibly softens fine texture. ## **Bitrate, rate control and measuring visible loss** Bitrate is the number of bits per second the encoded stream consumes, and rate control decides how the encoder spends them. Constant bitrate wastes bits on easy scenes, while constant-quality modes such as CRF let complexity drive the spend. Streaming encoders usually combine CRF with a VBV cap so player buffers stay predictable. "Without visible loss" is measured, not asserted. PSNR and SSIM are cheap but correlate weakly with perception; VMAF is the common choice for tuning adaptive bitrate (ABR) ladders. Per-title or per-scene encoding uses these scores to give a static talking head 1.5 Mb/s at 1080p and a grainy sports feed 6 Mb/s or more. A realistic 1080p rung for VOD, described setting by setting: - Encoder: libx264 in ffmpeg, preset slow (more motion search, smaller output, about 2 to 3 times the encode time of medium). - Rate control: CRF 23, capped at a 5 Mb/s maximum rate with a 10 Mb VBV buffer. - GOP: fixed 48 frames at 24 fps, scene-cut insertion disabled so IDR frames align across every ladder rung. - B-frames: 3, with adaptive placement; drop to 0 for low-latency live. - Output: fragmented MP4 (CMAF) segments, packaged once for both HLS and DASH. ## **Where the video compression codec sits in the delivery stack** The codec acts twice: at the encoder, before packaging, and at the decoder, in the viewer's device. Between them the CDN moves opaque, already-compressed segments. Edge caching does not re-compress video; it only multiplies whatever bitrate the encoder chose by the number of viewers. That makes compression the largest lever on delivery bandwidth. The arithmetic below assumes one million viewing hours a month at the top 1080p rung, with typical bitrates for equal perceived quality (our estimate, not a benchmark). | Codec | 1080p bitrate (typical) | Data per viewing hour | Monthly egress, 1M hours | | --- | --- | --- | --- | | H.264 / AVC (2003) | 5 Mb/s | 2.25 GB | 2,250 TB | | HEVC / H.265 (2013) | 3 Mb/s | 1.35 GB | 1,350 TB | | AV1 (2018) | 2.2 Mb/s | 0.99 GB | 990 TB | Moving the top rung from H.264 to AV1 removes about 1,260 TB a month at this audience size, before any CDN negotiation. Those savings only reach the invoice in full where egress is metered linearly. On [**BlazingCDN per-TB video delivery pricing**](https://blazingcdn.com/pricing/), which runs from $5 per TB down to $2.50 per TB at volume as of October 2026 with no request fees (current rates live on that pricing page), every terabyte the encoder removes comes off at the marginal rate. The trade-off is upstream: AV1 software encodes can take 5 to 10 times longer than x264 at comparable presets, and older devices lack hardware decode, so most ladders still ship H.264 as the fallback. ## **Video compression vs. containers, transcoding and HTTP compression** Video compression vs. container formats: the codec defines how pixels become bits; the container (MP4, MPEG-TS, WebM, Matroska) only wraps those bits with timing, metadata and audio. Changing MP4 to TS repackages without recompressing. Video compression vs. transcoding: transcoding is decoding one compressed stream and re-encoding it, often into several ladder rungs. Each lossy generation adds artifacts, so encode from the highest-quality mezzanine available. Video compression vs. HTTP compression: gzip, Brotli and zstd shrink text such as HLS playlists and DASH manifests, but they gain essentially nothing on encoded segments, which are already near maximum entropy. Serving segments through Brotli wastes CPU. ## **Common misconceptions about video codecs** - "A newer codec is always cheaper." Only if your audience can decode it in hardware; software decode of AV1 or VVC on low-end phones drains battery and drops frames. - "Bitrate equals quality." A 4 Mb/s per-title encode can score higher on VMAF than a fixed 6 Mb/s encode of the same content. - "Keyframes are free." Each IDR frame can be 5 to 20 times larger than a P-frame; a 1-second GOP for live can raise bitrate 10 to 15 percent at equal quality. - "B-frames are harmless for live." They require reordering and add at least one frame of latency each, which matters for LL-HLS targets near 2 seconds. ## **FAQ: Video compression and codecs** ### What is video compression in simple terms? Video compression is encoding video so it needs far fewer bits while still looking right to viewers. A codec stores one full picture occasionally, then describes later frames mostly as motion and small corrections. That reduces raw 1080p video from roughly 746 Mb/s to about 2 to 6 Mb/s, depending on the codec and content. ### Which video compression codec gives the smallest files? VVC (H.266) and AV1 give the smallest files among widely specified codecs, with AV1 the practical choice for web streaming in 2026. AV1 typically saves about 30 percent versus HEVC and around 50 percent versus H.264 at equal perceived quality, but encoding is much slower and older devices lack hardware decode support. ### Does video compression reduce quality? Lossy video compression always discards information, but well-tuned encodes keep the loss below what viewers notice. Visible artifacts such as blocking, banding and smeared texture appear when bitrate is too low for the content's complexity. Perceptual metrics like VMAF let encoding teams find the lowest bitrate that still scores as visually transparent. ### How much bandwidth does better video compression save a streaming service? Savings scale linearly with viewing hours and bitrate reduction. At one million viewing hours of 1080p a month, dropping from 5 Mb/s H.264 to 2.2 Mb/s AV1 cuts egress from about 2,250 TB to 990 TB. Real savings are smaller while H.264 fallback rungs still serve devices without AV1 decode. ## **Audit your top ladder rung this week** Pull a week of delivery logs and group bytes by rendition. In most VOD catalogs the top one or two rungs carry the majority of egress, so they are where codec and rate-control work pays back first. Re-encode ten representative titles at capped CRF in your current codec and in AV1, score each against the source with VMAF, and note the lowest bitrate that stays within one or two points of your current top rung. Multiply the bitrate difference by monthly viewing hours: that is your terabyte saving, and it also tells you how much device decode coverage you need before switching. BlazingCDN Video CDN replicates a pre-encoded library inside the CDN so the origin stays out of the delivery path, and you can review how it serves HLS and DASH renditions on the [**BlazingCDN Video CDN page for compressed video delivery**](https://blazingcdn.com/video-cdn/). 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The CDN for video and large traffic Their monthly bill vs ours - 20 TBFastly $2,087**$92.50** - 50 TBCDN77 $990**$215** - 200 TBCloudFront $11,965**$765** Published list prices, Aug 2026 [Calculate your cost](https://blazingcdn.com/cdn-cost-calculator/?utm_source=blog&utm_medium=sidebar&utm_campaign=blog_sidebar&utm_content=compare_calc) ## Related posts [![](https://blog.blazingcdn.com/hubfs/Gemini-Blog/image-Oct-06-2026-07-01-21-4738-AM.jpeg)](https://blog.blazingcdn.com/en-us/cdn-stream-optimization-adaptive-bitrate-low-latency-hls?hsLang=en-us) Learn ### [Adaptive Bitrate Streaming Best Practices: ABR and LL-HLS on a CDN](https://blog.blazingcdn.com/en-us/cdn-stream-optimization-adaptive-bitrate-low-latency-hls?hsLang=en-us) In 2026, most adaptive bitrate streaming failures on live channels come from the delivery path, not from the encoder. A ... Oct 6, 2026, 9:04:42โ€ฏAM [Read more](https://blog.blazingcdn.com/en-us/cdn-stream-optimization-adaptive-bitrate-low-latency-hls?hsLang=en-us) [![](https://blog.blazingcdn.com/hubfs/Gemini-Blog/image-Oct-05-2026-07-30-21-2326-AM.jpeg)](https://blog.blazingcdn.com/en-us/multicast-vs-unicast-how-video-reaches-many-viewers?hsLang=en-us) Learn ### [Multicast vs Unicast: How Video Reaches Many Viewers](https://blog.blazingcdn.com/en-us/multicast-vs-unicast-how-video-reaches-many-viewers?hsLang=en-us) In the multicast vs unicast decision for video, the verdict as of October 2026 is clear. Use unicast HTTP streaming ... 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All rights reserved. ```json { "@context" : "https://schema.org", "@id" : "https://blazingcdn.com/#organization", "@type" : "Organization", "description" : "High-volume CDN for video, live streaming, OTT/IPTV, software, games, SaaS and large-file delivery.", "logo" : { "@id" : "https://blazingcdn.com/#logo", "@type" : "ImageObject", "height" : 560, "url" : "https://blazingcdn.com/wp-content/uploads/2024/08/logo-560-560.png", "width" : 560 }, "name" : "BlazingCDN", "sameAs" : [ "https://www.linkedin.com/company/68261278", "https://x.com/BlazingCdn", "https://twitter.com/BlazingCdn", "https://www.facebook.com/BlazingCDN", "https://www.reddit.com/r/BlazingCDN/" ], "url" : "https://blazingcdn.com/" } ``` ```json { "@context" : "https://schema.org", "@id" : "https://blog.blazingcdn.com/#website", "@type" : "WebSite", "inLanguage" : "en-US", "name" : "BlazingCDN Blog", "publisher" : { "@id" : "https://blazingcdn.com/#organization" }, "url" : "https://blog.blazingcdn.com/" } ``` ```json { "@context" : "https://schema.org", "@id" : "https://blog.blazingcdn.com/en-us/what-is-video-compression-how-codecs-shrink-video#article", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "BlazingCDN" }, "dateModified" : "2026-10-06T07:32:09Z", "datePublished" : "2026-10-06T07:32:08Z", "description" : "What is video compression? Learn how a video compression codec shrinks files while preserving quality for faster streaming and storage.", "headline" : "What Is Video Compression? How Codecs Shrink Video", "image" : "https://143144902.fs1.hubspotusercontent-eu1.net/hubfs/143144902/Gemini-Blog/image-Oct-06-2026-07-30-20-2950-AM.jpeg", "inLanguage" : "en-us", "isPartOf" : { "@id" : "https://blog.blazingcdn.com/#website" }, "mainEntityOfPage" : { "@id" : "https://blog.blazingcdn.com/en-us/what-is-video-compression-how-codecs-shrink-video", "@type" : "WebPage" }, "publisher" : { "@id" : "https://blazingcdn.com/#organization" }, "wordCount" : 1639 } ``` ```json { "@context" : "https://schema.org", "@id" : "https://blog.blazingcdn.com/en-us/what-is-video-compression-how-codecs-shrink-video#breadcrumb", "@type" : "BreadcrumbList", "itemListElement" : [ { "@type" : "ListItem", "item" : "https://blog.blazingcdn.com/en-us", "name" : "Blog", "position" : 1 }, { "@type" : "ListItem", "item" : "https://blog.blazingcdn.com/en-us/what-is-video-compression-how-codecs-shrink-video", "name" : "What Is Video Compression? How Codecs Shrink Video", "position" : 2 } ] } ``` ```json { "@context" : "https://schema.org", "@id" : "https://blog.blazingcdn.com/en-us/what-is-video-compression-how-codecs-shrink-video#faq", "@type" : "FAQPage", "mainEntity" : [ { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Video compression is encoding video so it needs far fewer bits while still looking right to viewers. A codec stores one full picture occasionally, then describes later frames mostly as motion and small corrections. That reduces raw 1080p video from roughly 746 Mb/s to about 2 to 6 Mb/s, depending on the codec and content." }, "name" : "What is video compression in simple terms?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "VVC (H.266) and AV1 give the smallest files among widely specified codecs, with AV1 the practical choice for web streaming in 2026. AV1 typically saves about 30 percent versus HEVC and around 50 percent versus H.264 at equal perceived quality, but encoding is much slower and older devices lack hardware decode support." }, "name" : "Which video compression codec gives the smallest files?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Lossy video compression always discards information, but well-tuned encodes keep the loss below what viewers notice. Visible artifacts such as blocking, banding and smeared texture appear when bitrate is too low for the content's complexity. Perceptual metrics like VMAF let encoding teams find the lowest bitrate that still scores as visually transparent." }, "name" : "Does video compression reduce quality?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Savings scale linearly with viewing hours and bitrate reduction. At one million viewing hours of 1080p a month, dropping from 5 Mb/s H.264 to 2.2 Mb/s AV1 cuts egress from about 2,250 TB to 990 TB. Real savings are smaller while H.264 fallback rungs still serve devices without AV1 decode." }, "name" : "How much bandwidth does better video compression save a streaming service?" } ] } ```