Video Quality and Rendering

📹 Video Quality & Rendering

This guide covers all the options for controlling video output quality, resolution, encoding, and sharpness.

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Resolution Pipeline

Source Video → Download (--source-height) → Render (--render-height) → Final Output
   4K/2K/1080p       max / 1440 / 1080         source / 1440 / 1080

Source Download Height

Controls the maximum resolution downloaded from the source platform:

Value	Description
max (default)	Fetch the highest available quality
1080	Cap at 1080p
1440	Cap at 2K (1440p)
2160	Cap at 4K (2160p)

# Download highest quality available
python main.py --url "VIDEO_URL" --source-height max

# Cap at 1440p to save bandwidth
python main.py --url "VIDEO_URL" --source-height 1440

Render Output Height

Controls the final output video height:

Value	Description
1080 (default)	Standard HD output
1440	2K output
2160	4K output
source	Match the source video height

# Standard 1080p output
python main.py --url "VIDEO_URL" --render-height 1080

# Native 2K rendering
python main.py --url "VIDEO_URL" --source-height 1440 --render-height source

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Encoder Quality

CQ (NVENC — NVIDIA GPU Encoder)

Value	Quality	File Size
15-18	Ultra Sharp	Very Large
19-22	Sharp	Large
23 (default)	Standard	Balanced
24-28	Soft	Small
29-50	Blurry	Very Small

CRF (libx264 — CPU Encoder)

Value	Quality	File Size
15-17	Ultra Sharp	Very Large
18-19	Sharp	Large
20 (default)	Standard	Balanced
21-25	Soft	Small
26-50	Blurry	Very Small

# Ultra-sharp output
python main.py --url "VIDEO_URL" --video-cq 19 --video-crf 17

# Smaller files (lower quality)
python main.py --url "VIDEO_URL" --video-cq 28 --video-crf 25

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Encoder Preset

Controls the speed vs. quality tradeoff of the encoding process:

NVENC Presets (GPU)

p1 (fastest, lowest quality) → p7 (slowest, highest quality)

x264 Presets (CPU)

ultrafast → superfast → veryfast → faster → fast → medium → slow → slower → veryslow

# Slow encoding for maximum quality
python main.py --url "VIDEO_URL" --video-preset slow

# Fast encoding for quick preview
python main.py --url "VIDEO_URL" --video-preset veryfast

Use auto (default) to let the system choose the optimal preset.

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Bitrate

Value	Description
auto (default)	Resolution-aware: 4M (1080p), 8M (1440p), 12M (2K), 20M (4K)
8M	Fixed 8 Mbps
12M	Fixed 12 Mbps

# High bitrate for maximum quality
python main.py --url "VIDEO_URL" --video-bitrate 12M

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Sharpening

Apply a subtle sharpening filter for clearer output:

python main.py --url "VIDEO_URL" --video-sharpen

Best used in combination with high-resolution rendering:

# Ultra-HD 2K with sharpening
python main.py --url "VIDEO_URL" \
  --source-height 1440 \
  --render-height source \
  --video-sharpen

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Scaling Algorithm

Controls how the video is resized during rendering:

Algorithm	Description	Speed
lanczos (default)	Sharpest, preserves detail	Slowest
bicubic	Balanced quality	Medium
bilinear	Smooth but softer	Fast
area	Good for downscaling	Fast

python main.py --url "VIDEO_URL" --video-scale-algo lanczos

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Quality Presets (Recipes)

Maximum Quality (Slow)

python main.py --url "VIDEO_URL" \
  --source-height 2160 \
  --render-height source \
  --video-cq 18 \
  --video-crf 16 \
  --video-preset slow \
  --video-scale-algo lanczos \
  --video-sharpen \
  --video-bitrate 20M

Standard Quality (Default)

python main.py --url "VIDEO_URL"
# Uses: source-height max, render-height 1080, cq 23, crf 20, lanczos

Fast Preview (Low Quality)

python main.py --url "VIDEO_URL" \
  --source-height 1080 \
  --video-cq 30 \
  --video-crf 28 \
  --video-preset veryfast \
  --video-scale-algo bilinear

TikTok/Reels Optimized

python main.py --url "VIDEO_URL" \
  --source-height 1440 \
  --render-height 1080 \
  --video-cq 21 \
  --video-crf 19 \
  --video-sharpen

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See Also

• CLI Reference — Full list of quality flags
• Google Colab Guide — Quality settings for cloud GPUs