Video Codec Comparison Guide: H.264, H.265, VP9, AV1
Choosing the right video codec and bitrate is crucial for balancing quality and file size. This guide explains how to compare video codecs objectively using DualView, what artifacts to look for, and how to find the optimal settings for your content.
Major Video Codecs Compared
| Codec | Container | Compression | Support | Best For |
|---|---|---|---|---|
| H.264/AVC | MP4, MKV | Good | Universal | Maximum compatibility |
| H.265/HEVC | MP4, MKV | Better (~50% smaller) | Wide (not universal) | 4K, limited bandwidth |
| VP9 | WebM | Similar to H.265 | Browsers, YouTube | Web streaming |
| AV1 | WebM, MP4 | Best (~30% smaller than H.265) | Growing | Future-proofing |
Compression Artifacts to Look For
Blocking
Square blocks visible in areas of subtle gradient or solid color. Most common at low bitrates.
Banding
Visible steps in gradients instead of smooth transitions. Common in skies and vignettes.
Mosquito Noise
Shimmering artifacts around high-contrast edges, especially around text and sharp lines.
Ringing
Echo-like patterns around sharp edges, appearing as light or dark halos.
Blurring
Loss of fine detail and texture, making the image look soft or smeared.
Color Bleeding
Colors spreading beyond their boundaries, especially at high compression.
Comparison Methodology
Step 1: Prepare Your Source
Start with the highest quality source available. If comparing codecs, use the same source for all encodes. Ideally, use a lossless or very high bitrate master.
Step 2: Encode Multiple Versions
Create encodes at different bitrates or with different codecs. For a thorough comparison:
- Encode at 3-5 different bitrates per codec
- Use the same encoder settings (CRF, preset, etc.)
- Keep all other variables constant
Step 3: Load into DualView
- Load source and compressed version (or two compressed versions)
- Use synchronized playback to compare the same frames
- Pause on problem areas (high motion, gradients, detailed textures)
- Use difference heatmap to highlight changed pixels
- Check quality metrics (PSNR, SSIM) for objective measurements
Compression artifacts are worst during high motion or scene changes. Scrub through the video and pause on fast-moving scenes, explosions, or busy backgrounds to find the worst-case frames.
Understanding Quality Metrics
PSNR (Peak Signal-to-Noise Ratio)
Measures pixel-level difference from the original. Higher is better.
- >40 dB — Excellent, nearly lossless
- 35-40 dB — Very good quality
- 30-35 dB — Good quality, some artifacts visible
- <30 dB — Noticeable quality loss
SSIM (Structural Similarity Index)
Measures perceived similarity based on structure. Range 0-1, higher is better.
- >0.98 — Excellent, indistinguishable
- 0.95-0.98 — Very good, minor differences
- 0.90-0.95 — Good, some visible differences
- <0.90 — Noticeable quality loss
Practical Bitrate Guidelines
| Resolution | H.264 (Good) | H.265 (Good) | AV1 (Good) |
|---|---|---|---|
| 1080p 30fps | 8-12 Mbps | 4-6 Mbps | 3-5 Mbps |
| 1080p 60fps | 12-20 Mbps | 6-10 Mbps | 5-8 Mbps |
| 4K 30fps | 35-50 Mbps | 15-25 Mbps | 12-20 Mbps |
| 4K 60fps | 50-80 Mbps | 25-40 Mbps | 20-30 Mbps |
These are starting points — use DualView to compare and adjust based on your specific content. Animation may need less bitrate than live action; grain needs more.
When to Use Each Codec
H.264
- Need universal playback compatibility
- Targeting older devices or browsers
- DVD/Blu-ray authoring
H.265/HEVC
- 4K content with limited storage/bandwidth
- Apple ecosystem (native support)
- When you can verify target device support
VP9
- YouTube uploads (processed server-side)
- Web-only distribution
- Avoiding patent licensing (royalty-free)
AV1
- Maximum compression efficiency needed
- Future-proofing your archive
- Streaming services (Netflix, YouTube already use it)