Audio controls¶

The General tab carries the controls that apply regardless of which encoder you pick. Not every encoder honours all of them - the encoder reference says which apply to each, and the DeeZy adapters disable most of them deliberately.

Sample rate and channel layout¶

Both default to Preserve, meaning the source value is carried through untouched.

The choices offered are the encoder's, not a generic list: ffmpeg.libopus offers Opus's five rates, ffmpeg.libmp3lame offers MP3's nine, and the layouts are similarly restricted to what the codec can actually represent.

The DeeZy adapters go further and reject layouts that would require an upmix, since Dolby encoding treats that as a different operation entirely.

Gain¶

−30 to +30 dB, in 0.5 dB steps, applied by FFmpeg before the encoder sees the audio. Leave it at 0 dB unless you have a reason.

Time modification and tempo¶

These two rows are one control. Time modification is a list of named conversions; Tempo is the ratio the encoder actually receives. Picking a conversion fills in the ratio, and typing a ratio by hand sets the list to Custom.

The list holds every conversion between 23.976, 24, 25, 29.97, 30, 50, 59.94, and 60 fps, grouped by source rate, plus a set of plain speed multipliers from 0.25× to 4×. So the common job - a 24 fps mix that needs to sit under a 23.976 fps picture - is one selection rather than an arithmetic exercise:

Ratios are computed from the exact framerates - 23.976 fps is really 24000/1001 - not from the rounded labels.

The Tempo field spans 0.25× to 4× directly, for anything the list does not name. Values below 0.5× or above 2× are split into several atempo stages automatically, since a single one cannot go further.

This changes duration without changing pitch. As with gain, it is applied during decode, so both rows are unavailable for the DeeZy adapters.

Audio delay¶

The delay field takes a signed value in milliseconds, and it is applied by editing the samples rather than by writing a container offset:

• Positive - prepend that much silence.
• Negative - trim that much from the beginning.

The application detects a starting value per track and shows where it came from in the line beneath the field. The value stays editable; detection is a suggestion, not a lock.

Container delays¶

For inputs that contain video, the bundled MediaInfo library reports each audio track's delay relative to the reference video track. This is the normal case for a file demuxed from a Blu-ray or a broadcast capture, where the audio genuinely starts at a different point from the picture.

Detection is per track, so switching Audio stream updates the delay. When MediaInfo cannot match its track list to the ffprobe stream list unambiguously, the status line says so and the field stays at zero rather than guessing.

Filename markers¶

For single-track, audio-only inputs there is no video to measure against, so the filename is used instead. A marker is recognised in three shapes, case-insensitively:

The separator between delay and the number can be whitespace, _, ., :, or =. The number may be signed and fractional.

Two rules keep this from misfiring:

• Exactly one marker must be present. A filename containing two is ignored entirely.
• The value must be finite and no larger than 24 hours (86,400,000 ms).

When a marker is used, it is stripped from the generated output name - the delay has been baked into the samples, so carrying the marker forward would be a lie about the new file. Leftover separator runs are tidied up, so Track [DELAY -21ms].ac3 becomes Track.opus rather than Track -.opus.

Custom arguments¶

Every FFmpeg adapter and standalone encoder exposes a Custom arguments field at the bottom of its Options tab, for the occasional flag the curated options do not cover - -cutoff 18000, for instance.

It takes one argument group per line, is never run through a shell, and can place a line before -i, extend the managed filter chain rather than replacing it, and override a managed setting while reporting what it displaced.

See Custom arguments for the whole thing.