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: max, high, medium, low.
• audioQuality overrides quality for audio specifically.
• videoQuality overrides quality for video specifically.

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	Target	Description
max	Lossless or ~256 kbps	ALAC if device supports it and source is lossless; otherwise same as high
high	~256 kbps	Transparent quality (default)
medium	~192 kbps	Excellent quality
low	~128 kbps	Good quality, space-efficient

All presets use VBR encoding by default. Set encoding = "cbr" globally or per device for constant bitrate encoding. See Audio Transcoding for full details.

The max Preset

The max preset is device-aware. On devices that support Apple Lossless (iPod Classic, Video 5G/5.5G, Nano 3G-5G), it produces ALAC from lossless sources. On other devices, it falls back to the same high-quality AAC as the high preset.

• Compatible lossy sources (MP3, AAC) are always copied as-is, regardless of preset
• Incompatible lossy sources (OGG, Opus) are transcoded with the bitrate capped at the source bitrate

File Size Estimates

For a 4-minute song:

Preset	Approx Bitrate	File Size
max (ALAC)	~900 kbps	~26 MB
max (AAC fallback)	~256 kbps	~7.5 MB
high	~256 kbps	~7.5 MB
medium	~192 kbps	~5.6 MB
low	~128 kbps	~3.8 MB

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

VBR vs CBR

Mode	Description
VBR (default)	Variable bitrate — adapts to content complexity. Better quality-per-MB.
CBR	Constant bitrate — predictable file sizes. More reliable preset change detection.

VBR is recommended for most uses. VBR AAC works correctly for seeking on iPods. Use encoding = "cbr" if you want predictable file sizes or guaranteed detection of preset changes between adjacent tiers.

Encoder Mapping

FFmpeg encoder settings by preset:

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

When max resolves to ALAC (on capable devices with lossless sources), the ALAC encoder is used instead. When max falls back to AAC, it uses the same encoder settings as high.

Note: The aac_at encoder (macOS AudioToolbox) uses an inverted quality scale where 0 is highest quality and 14 is lowest. The native aac and libfdk_aac encoders use a scale where higher values mean higher quality. podkit maps target bitrates to the correct aac_at quality value automatically.

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)

Changing Presets

When you change your quality preset, podkit detects that existing transcoded tracks on the iPod don’t match the new target bitrate and re-transcodes them on the next sync. Play counts, star ratings, and playlist membership are preserved.

This applies to lossless source tracks only. Lossy sources (MP3, AAC) are copied as-is regardless of the preset.

See Track Upgrades for details.

Choosing a Preset

For Audio

Use Case	Recommended Preset
Audiophile, large storage	max (ALAC on supported devices)
Best quality, reasonable size	high (default)
Limited storage	medium
Minimum storage	low
Predictable file sizes	Any preset with encoding = "cbr"

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