resize

Change video resolution with preset scales or custom dimensions while preserving quality.

Overview

The resize command is your go-to tool for changing video resolution, whether you're optimizing for specific platforms (YouTube, Instagram, TikTok), reducing file sizes for mobile devices, or upscaling content for high-resolution displays. It intelligently maintains aspect ratios, provides industry-standard resolution presets, and offers advanced controls for professional-grade output.

Key Features:

• 🎯 Preset resolutions from 360p to 8K (4320p)
• 🔄 Custom dimensions with automatic aspect ratio handling
• 🎬 Multiple codec support (H.264, H.265, VP9, AV1)
• ⚡ Hardware acceleration for faster processing
• 🎨 Built-in rotation, flipping, and cropping tools
• 📐 Smart padding to ensure codec compatibility

Common Use Cases:

• Preparing videos for social media platforms
• Creating mobile-optimized versions for bandwidth savings
• Upscaling old content to modern standards
• Converting between aspect ratios (16:9 ↔ 4:3 ↔ 1:1)
• Batch processing entire video libraries

Usage

Options

Basic Options

Video Codec & Quality

Resolution & Aspect Ratio

Transformation

Performance & Output

Flag Details

--scale - Resolution Control

Specify target resolution using presets or custom dimensions:

Preset Values:

• 360p = 640×360 (mobile, low bandwidth)
• 480p = 854×480 (SD quality)
• 720p = 1280×720 (HD)
• 1080p = 1920×1080 (Full HD) ← default
• 1440p = 2560×1440 (QHD)
• 2160p = 3840×2160 (4K UHD)
• 4320p = 7680×4320 (8K UHD)

Custom Dimensions:

• Format: WIDTHxHEIGHT (e.g., 1920x1080, 1280x720)
• Dimensions are automatically rounded to even numbers (required for H.264/H.265)
• Aspect ratio is preserved with letterboxing/pillarboxing if needed

Learn More:

• Video Resolution Standards
• FFmpeg Scale Filter

--codec - Video Encoder

Choose the video codec based on compatibility, quality, and file size needs:

H.264 (h264) - Default

• Compatibility: Universal (all devices, browsers, players)
• Encoding Speed: Fast
• Compression: Good
• File Size: Baseline reference
• Use When: Maximum compatibility needed, live streaming, quick encoding

H.265 (h265) - HEVC

• Compatibility: Modern devices (2016+), some browsers
• Encoding Speed: Slow (2-3x longer than H.264)
• Compression: Excellent (40-50% smaller than H.264 at same quality)
• File Size: Much smaller
• Use When: 4K video, storage optimization, modern device distribution

VP9 (vp9)

• Compatibility: Web browsers, YouTube
• Encoding Speed: Very slow
• Compression: Excellent (similar to H.265)
• File Size: Small
• Use When: WebM format, YouTube uploads, open-source projects

AV1 (av1)

• Compatibility: Latest browsers/devices (2020+)
• Encoding Speed: Extremely slow
• Compression: Best (20-30% better than H.265)
• File Size: Smallest
• Use When: Future-proofing, maximum compression, latest platforms

Learn More:

• H.264 vs H.265 Comparison
• FFmpeg Codecs Documentation

--quality - CRF (Constant Rate Factor)

CRF controls encoding quality from 0 (lossless) to 51 (worst quality). Unlike bitrate, CRF adapts to video complexity.

Recommended Values:

• 15-18: Near-lossless, master copies, archival (very large files)
• 20-23: High quality, professional distribution, streaming ← 23 is default
• 24-28: Good quality, web delivery, mobile
• 29-35: Low quality, preview/draft, maximum compression

Quality vs File Size:

• Each +6 CRF roughly halves file size
• Visual quality degrades more noticeably above CRF 28
• H.265/VP9 can use +4-6 CRF higher than H.264 for same perceived quality

Learn More:

• FFmpeg CRF Guide

--preset - Encoding Speed vs Compression

Presets control how much time FFmpeg spends optimizing compression. Slower = better compression.

Available Presets:

• ultrafast - 10x faster, +20-30% larger files
• superfast - 5x faster, +15-20% larger files
• veryfast - 3x faster, +10-15% larger files
• faster - 2x faster, +5-10% larger files
• fast - 1.5x faster, +5% larger files
• medium - Balanced speed/quality ← default
• slow - 1.5x slower, 5-10% smaller files, better quality
• slower - 2x slower, 10-15% smaller files, better quality
• veryslow - 3x+ slower, 15-20% smaller files, best quality

Recommendations:

• Quick tests: fast or faster
• Production: slow or veryslow
• Live streaming: ultrafast or veryfast
• Archival/Distribution: veryslow + two-pass

Learn More:

• FFmpeg Preset Documentation

--bitrate - Target Bitrate

Set a target bitrate in Mbps. Overrides CRF-based quality control.

Format:

• 2M = 2 Mbps (megabits per second)
• 5M = 5 Mbps
• 10M = 10 Mbps

Recommended Bitrates by Resolution:

--aspect - Force Aspect Ratio

Override the output aspect ratio, adding letterboxing/pillarboxing as needed.

Common Ratios:

• 16:9 - Widescreen (YouTube, TV, monitors)
• 4:3 - Classic TV, older content
• 21:9 - Ultrawide cinema
• 1:1 - Square (Instagram posts, profile videos)
• 9:16 - Vertical (Instagram Stories, TikTok, Reels)

Behavior:

• Content is scaled to fit within the specified ratio
• Black bars (letterboxing/pillarboxing) added if necessary
• Original video is never stretched or distorted

--fps - Frame Rate

Change the output frame rate (frames per second).

Common Frame Rates:

• 24 - Cinema standard, film look
• 25 - PAL video standard
• 30 - NTSC video standard, most web content
• 60 - High frame rate, smooth motion, gaming
• 120 - Very smooth, gaming, sports

Note: Increasing FPS requires interpolation (creating new frames) which may introduce artifacts. Decreasing FPS is straightforward but may appear choppy.

--scale-algo - Scaling Algorithm

Choose the algorithm used for resizing pixels.

Available Algorithms:

Lanczos (default) - Best Quality

• Highest quality, sharpest results
• Slightly slower
• Best for: Downscaling, professional work

Bicubic - Balanced

• Good quality, smooth results
• Moderate speed
• Best for: General use, slight softness preferred

Bilinear - Fast

• Lower quality, softer results
• Fastest algorithm
• Best for: Quick previews, when speed matters

Spline - Smooth

• Very smooth, can be slightly soft
• Good speed
• Best for: Artistic looks, reducing aliasing

Learn More:

• Image Scaling Algorithms

--rotate - Rotation

Rotate video by specified degrees. Metadata-based rotation is automatically corrected.

Values: 90, 180, 270 (degrees clockwise)

Examples:

• Portrait to landscape: --rotate 90
• Upside-down correction: --rotate 180
• Landscape to portrait: --rotate 270

--flip - Mirroring

Flip video horizontally, vertically, or both.

Values:

• horizontal - Mirror left/right
• vertical - Mirror top/bottom
• both - Both axes (equivalent to 180° rotation + horizontal flip)

--crop - Cropping

Remove portions of the video frame.

Format Options:

Preset Ratios:

• 16:9 - Widescreen crop
• 4:3 - Classic crop
• 1:1 - Square crop (centered)

Custom Crop:

• Format: width:height:x:y
• width - Crop width in pixels
• height - Crop height in pixels
• x - X offset from left
• y - Y offset from top

Example: --crop 1920:1080:0:140 (crop 1920×1080 starting at top-left with 140px offset from top)

--two-pass - Two-Pass Encoding

Enable two-pass encoding for optimal quality at a target bitrate.

How It Works:

1. First Pass: Analyzes entire video, collects statistics
2. Second Pass: Encodes video using statistics for optimal bit distribution

Advantages:

• Better quality at same file size
• More efficient bitrate usage
• Smoother quality across entire video

Disadvantages:

• Takes 2x time (processes video twice)
• Requires temporary disk space for pass data

When to Use:

• Target bitrate is specified (--bitrate)
• Quality is critical (final distribution)
• File size must meet strict requirements

--hw-accel - Hardware Acceleration

Enable GPU-accelerated encoding (NVIDIA, AMD, Intel, Apple Silicon).

Speed Improvement: 5-10x faster encoding

Requirements:

• Compatible GPU with hardware encoder
• Proper drivers installed
• FFmpeg compiled with hardware support

Limitations:

• Slightly lower quality than CPU encoding
• Not all codecs supported on all GPUs
• May have limited preset/option support

Supported:

• NVIDIA NVENC (h264, h265)
• Intel Quick Sync (h264, h265)
• AMD VCE (h264, h265)
• Apple VideoToolbox (h264, h265)

Learn More:

• FFmpeg Hardware Acceleration

Resolution Presets

Examples

Basic Resizing

Folder Support

Advanced Codec Options

Custom Aspect Ratio

Frame Rate Control

Rotation and Flip

Cropping

Hardware Acceleration

Bitrate Control

Dry Run Preview

# Preview resize operation
mediaproc video resize video.mp4 --scale 720p --dry-run

Output:

Batch Resizing

# Resize all MP4 files to 720p
for file in *.mp4; do
  mediaproc video resize "$file" --scale 720p -o 720p/
done

# Create multiple versions
for file in *.mp4; do
  mediaproc video resize "$file" --scale 1080p -o 1080p/
  mediaproc video resize "$file" --scale 720p -o 720p/
  mediaproc video resize "$file" --scale 480p -o 480p/
done

Use Cases

Mobile Optimization

Reduce resolution for mobile devices and data savings:

# Standard mobile (720p)
mediaproc video resize video.mp4 --scale 720p

# Low bandwidth mobile (480p)
mediaproc video resize video.mp4 --scale 480p

# Very low bandwidth (custom small size)
mediaproc video resize video.mp4 -w 640

Web Streaming

Create appropriate sizes for web delivery:

# Standard web (1080p)
mediaproc video resize source.mp4 --scale 1080p -o web-hd.mp4

# Medium quality (720p)
mediaproc video resize source.mp4 --scale 720p -o web-sd.mp4

# Low bandwidth (480p)
mediaproc video resize source.mp4 --scale 480p -o web-mobile.mp4

Social Media

Resize for platform requirements:

# Instagram feed (1080x1080)
mediaproc video resize video.mp4 -w 1080 -h 1080 --pad

# Instagram story (1080x1920 vertical)
mediaproc video resize horizontal.mp4 -w 1080 -h 1920 --pad

# Twitter (1280x720 recommended)
mediaproc video resize video.mp4 --scale 720p

# TikTok (1080x1920 vertical)
mediaproc video resize video.mp4 -w 1080 -h 1920 --pad

# YouTube thumbnail video (1920x1080)
mediaproc video resize video.mp4 --scale 1080p

4K Downscaling

Convert high-resolution footage to standard sizes:

# 4K to standard HD
mediaproc video resize 4k-footage.mp4 --scale 1080p

# 4K to gaming/monitor standard
mediaproc video resize 4k-footage.mp4 --scale 1440p

# 4K to mobile
mediaproc video resize 4k-footage.mp4 --scale 720p

Adaptive Streaming

Create multiple resolutions for adaptive bitrate:

# Create streaming ladder
mediaproc video resize source.mp4 --scale 1080p -o 1080p.mp4
mediaproc video resize source.mp4 --scale 720p -o 720p.mp4
mediaproc video resize source.mp4 --scale 480p -o 480p.mp4

# Then transcode each to different bitrates
mediaproc video transcode 1080p.mp4 --bitrate 5M -o 1080p-5mbps.mp4
mediaproc video transcode 720p.mp4 --bitrate 2.5M -o 720p-2.5mbps.mp4
mediaproc video transcode 480p.mp4 --bitrate 1M -o 480p-1mbps.mp4

Email-Friendly Videos

Create small videos for email attachments:

# Small resolution + compression
mediaproc video resize large-video.mp4 --scale 480p -o small.mp4
mediaproc video compress small.mp4 -q low -o email-ready.mp4

Technical Details

Aspect Ratio Preservation

The plugin automatically maintains aspect ratio:

Width only specified:

• Height calculated to maintain aspect ratio
• No distortion

Height only specified:

• Width calculated to maintain aspect ratio
• No distortion

Both specified (without --pad):

• Scales to fit within dimensions
• Maintains aspect ratio
• May not use full width or height

Both specified (with --pad):

• Scales to fit
• Adds black bars (letterbox/pillarbox)
• Fills exact dimensions

Scaling Algorithm

Uses FFmpeg's bicubic scaling (high quality):

# Downscaling (4K to 1080p)
-vf scale=1920:1080

# Upscaling (720p to 1080p) - not recommended
-vf scale=1920:1080

Even Dimensions

Video codecs require even dimensions (divisible by 2):

• Input: 1920x1080 → Valid ✓
• Input: 1921x1080 → Adjusted to 1920x1080 ✓
• Custom: 1281x720 → Adjusted to 1280x720 ✓

The plugin automatically ensures even dimensions.

Quality Preservation

Resizing uses default CRF 23 for re-encoding:

• Minimal quality loss with good compression
• Same as original if source is lower quality
• Can combine with compress for more size reduction

Padding Behavior

When --pad is used:

# 16:9 video → 1:1 square
mediaproc video resize 1920x1080.mp4 -w 1080 -h 1080 --pad
# Result: Video scaled to 1080x608, black bars top/bottom

# 1:1 square → 16:9
mediaproc video resize 1080x1080.mp4 -w 1920 -h 1080 --pad
# Result: Video scaled to 1080x1080, black bars left/right

Performance Considerations

Processing Speed

Resizing speed depends on:

• Resolution change: Larger changes take longer
• Downscaling: Fast (throwing away pixels)
• Upscaling: Slower (interpolating pixels)
• Video length: Proportional to duration

Approximate speeds (1080p to 720p):

• ~0.5-1x real-time for downscaling
• ~0.3-0.5x real-time for upscaling

Disk Usage

No temporary files created. Output written directly.

Memory Usage

Memory scales with source resolution:

• 1080p: ~500 MB RAM
• 4K: ~2 GB RAM

Error Handling

Common Errors

No dimensions specified:

Invalid preset:

Dimensions too large:

Invalid dimensions:

Best Practices

1. Downscale only: Upscaling reduces quality
2. Use presets: Easier than custom dimensions
3. Test with --dry-run: Preview before processing
4. Combine with compress: Further reduce file size after resizing
5. Keep originals: Never resize source files
6. Match aspect ratio: Avoid distortion
7. Use padding for social: Exact dimensions with --pad
8. Batch process: Create multiple sizes efficiently

Troubleshooting

Output Looks Distorted

Video appears stretched or squashed:

Cause: Specified dimensions don't match source aspect ratio

Solution 1: Use preset

mediaproc video resize video.mp4 --scale 1080p

Solution 2: Use padding

mediaproc video resize video.mp4 -w 1920 -h 1080 --pad

Solution 3: Specify only width or height

mediaproc video resize video.mp4 -w 1920

Quality Loss

Resized video has artifacts or looks blurry:

Cause 1: Upscaling from lower resolution

• Don't upscale, keep original or downscale only

Cause 2: Too aggressive downscaling

# Better: Gradual downscaling
mediaproc video resize 4k.mp4 --scale 1440p
mediaproc video resize output_2560x1440.mp4 --scale 1080p

Cause 3: Source already compressed

• Quality can't improve beyond source

Processing Too Slow

Resizing takes too long:

Solution: Resize before other operations

# Efficient: Resize first (less data to process)
mediaproc video resize video.mp4 --scale 1080p
mediaproc video compress video_1920x1080.mp4

# Inefficient: Resize after (more data)
mediaproc video compress video.mp4
mediaproc video resize video_compressed.mp4 --scale 1080p

File Size Not Reduced

Resized video is still large:

Solution: Combine with compression

mediaproc video resize 4k.mp4 --scale 1080p
mediaproc video compress output_1920x1080.mp4 -q medium

Advanced Examples

Social Media Batch Export

#!/bin/bash
# Create versions for all social platforms

input="source.mp4"

# Instagram feed (square)
mediaproc video resize "$input" -w 1080 -h 1080 --pad -o instagram-feed.mp4

# Instagram story (vertical)
mediaproc video resize "$input" -w 1080 -h 1920 --pad -o instagram-story.mp4

# YouTube (standard)
mediaproc video resize "$input" --scale 1080p -o youtube.mp4

# Twitter (720p recommended)
mediaproc video resize "$input" --scale 720p -o twitter.mp4

# TikTok (vertical)
mediaproc video resize "$input" -w 1080 -h 1920 --pad -o tiktok.mp4

Adaptive Streaming Versions

#!/bin/bash
# Create multiple resolutions for adaptive streaming

input="source-4k.mp4"

resolutions=("1080p" "720p" "480p")

for res in "${resolutions[@]}"; do
  echo "Creating $res version..."
  mediaproc video resize "$input" --scale "$res" -o "stream-$res.mp4"
done

echo "All versions created:"
ls -lh stream-*.mp4

Aspect Ratio Conversion

#!/bin/bash
# Convert 16:9 to different aspect ratios

input="16x9-video.mp4"

# 4:3 (classic TV)
mediaproc video resize "$input" -w 1440 -h 1080 --pad -o 4x3.mp4

# 21:9 (ultrawide)
mediaproc video resize "$input" -w 2560 -h 1080 --pad -o 21x9.mp4

# 1:1 (square)
mediaproc video resize "$input" -w 1080 -h 1080 --pad -o 1x1.mp4

# 9:16 (vertical)
mediaproc video resize "$input" -w 1080 -h 1920 --pad -o 9x16.mp4

Progressive Downscaling

#!/bin/bash
# Progressively downscale for quality testing

input="4k-video.mp4"
current="$input"

scales=("1440p" "1080p" "720p" "480p")

for scale in "${scales[@]}"; do
  output="downscaled-$scale.mp4"
  echo "Downscaling to $scale..."
  mediaproc video resize "$current" --scale "$scale" -o "$output"
  current="$output"
done

Resolution Detection and Conditional Resize

#!/bin/bash
# Only resize if resolution exceeds threshold

input="$1"
max_width=1920

# Get current width using ffprobe
width=$(ffprobe -v error -select_streams v:0 -show_entries stream=width -of default=nv=1:nk=1 "$input")

if [ "$width" -gt "$max_width" ]; then
  echo "Video width $width exceeds $max_width, resizing..."
  mediaproc video resize "$input" -w "$max_width"
else
  echo "Video width $width is within limits, no resize needed"
fi

Related Commands

• compress - Reduce file size after resizing
• transcode - Change format/codec during resize
• trim - Cut video before resizing to save processing time

See Also

• FFmpeg Scaling Documentation
• Video Resolution Standards
• Aspect Ratio Guide