Quality Presets

Detailed specifications for podkit’s audio and video transcoding presets.

Unified vs Specific Quality

podkit uses a layered quality system:

• quality sets a baseline for both audio and video. Values common to both (max, high, medium, low) apply to everything. Audio-only values like lossless and CBR variants are accepted but only affect audio.
• audioQuality overrides quality for audio specifically. Accepts all audio presets.
• videoQuality overrides quality for video specifically. Accepts max, high, medium, low.

This lets you use a single quality setting for simplicity, or fine-tune audio and video independently. See Config File Reference for the full resolution chain.

Audio Presets

Preset Summary

Preset	Type	Target	Description
lossless	Lossless	N/A	Apple Lossless (only from lossless sources)
max	VBR	~320 kbps	Highest VBR quality level
max-cbr	CBR	320 kbps	Guaranteed 320 kbps
high	VBR	~256 kbps	Transparent quality (default)
high-cbr	CBR	256 kbps	Predictable file sizes
medium	VBR	~192 kbps	Excellent quality
medium-cbr	CBR	192 kbps
low	VBR	~128 kbps	Good quality, space-efficient
low-cbr	CBR	128 kbps

File Size Estimates

For a 4-minute song:

Preset	Mode	Approx Bitrate	File Size
lossless	Lossless	~900 kbps	~26 MB
max	VBR	~320 kbps	~9.4 MB
high	VBR	~256 kbps	~7.5 MB
medium	VBR	~192 kbps	~5.6 MB
low	VBR	~128 kbps	~3.8 MB

VBR file sizes vary based on content complexity. CBR sizes are exact.

VBR vs CBR

Mode	Description
VBR	Variable bitrate - adapts to content complexity. Better quality-per-MB.
CBR	Constant bitrate - predictable file sizes. May waste bits on simple passages.

VBR is recommended for most uses. VBR AAC works correctly for seeking on iPods.

Lossless Preset

The lossless preset produces Apple Lossless (ALAC) files:

• Lossless - No quality loss from original
• Larger files - Approximately 50-60% of original lossless size
• Source requirement - Only applies to lossless sources (FLAC, WAV, AIFF, ALAC)
• Lossy quality - Lossy sources use the lossyQuality preset (default: max)

Encoder Mapping

FFmpeg encoder settings by preset:

Preset	Native AAC (-q:a)	libfdk_aac (-vbr)	aac_at (-q:a)
max/high	5	5	14
medium	4	4	11
low	2	3	6

Video Presets

Preset Summary

Preset	Description	Recommended For
max	Highest quality, largest files	Best viewing, ample storage
high	Excellent quality (default)	General use
medium	Good quality, smaller files	Limited storage
low	Space-efficient	Maximum capacity

Bitrate by Device and Preset

Preset	iPod Classic (640x480)	iPod Video (320x240)
max	640x480 @ 2500 kbps	320x240 @ 768 kbps
high	640x480 @ 2000 kbps	320x240 @ 600 kbps
medium	640x480 @ 1500 kbps	320x240 @ 400 kbps
low	640x480 @ 1000 kbps	320x240 @ 300 kbps

File Size Estimates

For a 2-hour movie on iPod Classic:

Preset	Approx Size
max	~2.2 GB
high	~1.8 GB
medium	~1.3 GB
low	~900 MB

Source Quality Awareness

Video quality is capped to source quality:

Source Quality	User Setting	Effective Output
1080p @ 8 Mbps	high	640x480 @ 2000 kbps
480p @ 1.5 Mbps	high	480p @ 1500 kbps (capped)
360p @ 800 kbps	high	360p @ 800 kbps (source limited)

Choosing a Preset

For Audio

Use Case	Recommended Preset
Audiophile, large storage	lossless with lossyQuality = "max"
Best quality, reasonable size	high (default)
Limited storage	medium
Minimum storage	low
Predictable file sizes	Any -cbr variant

For Video

Use Case	Recommended Preset
Best viewing experience	max
General use	high (default)
Limited storage	medium
Maximum capacity	low

See Also

• Audio Transcoding - Full audio transcoding documentation
• Video Transcoding - Video transcoding and configuration
• Configuration - Setting presets in config