VHS output is nearly silent: inspect audio dtype before increasing gain
This case-led guide concerns a reported fp16-intermediate scenario, not every silent track. First establish whether audio exists and is valid before composition.
Symptoms and scope
This case-led guide concerns a reported fp16-intermediate scenario, not every silent track. First establish whether audio exists and is valid before composition.
Error fragments for search; IDs, values and filenames may vary:
VHS_VideoCombine
--fp16-intermediates
silent audio
Source-supported context
Issue #708, opened August 26, 2026, reports a comparison between VHS and core saving. In the currently checked VHS source, VideoCombine tells ffmpeg to read f32le but passes waveform.numpy().tobytes() without an explicit float32 cast at that point. This supports the report's proposed dtype-mismatch mechanism if the waveform is not float32. The measurements and workaround remain the reporter's; this site has not reproduced them or verified a released fix. Issue report VHS source
Cases to distinguish
1. Audio is disconnected, the track is absent or playback volume is the simpler problem.
2. Valid upstream audio is serialized under an incompatible dtype assumption in a particular node version.
3. An earlier effect or decoder already produced abnormal audio.
Diagnostic sequence
The sequence below is an editorial procedure based on the cited context, not a diagnosis already confirmed for your environment.
Step 1. Check that the file has an audio track and compare the original preview with the combined result before adding gain.
Step 2. Record launch flags, core and VHS versions. If an audio debug view exposes the upstream waveform dtype, capture it; compare the finding with the reported --fp16-intermediates case rather than assuming every silent track is fp16.
Step 3. In a copy of the workflow, send the same upstream AUDIO to both VHS_VideoCombine and a currently supported core CreateVideo/SaveVideo route. Check each resulting file for an audio track, duration and level. If testing without --fp16-intermediates, record memory use and change no other setting.
Step 4. Apply updates only for a relevant documented fix; do not paste an issue's source patch into arbitrary versions. Report a minimal graph and redacted logs.
Completion check
Original and combined audio have reasonable audible content, duration and amplitude, with repeatable differences across save paths rather than amplified noise.
Limitations and cautions
The checked source shows a potentially mismatched byte-format path, but does not prove that every VHS release or installation exhibits the reported sound level. Disabling a flag is only a controlled comparison, not a universal repair.
Original sources
- VHS audio dtype report under fp16 intermediates — checked 2026-09-26.
- VideoHelperSuite source — checked 2026-09-26.
- VideoHelperSuite README — checked 2026-09-26.
Source and English-language review: 2026-09-26. The issue measurements are third-party observations; no site-run audio workflow, GPU test or runtime guarantee is supplied.
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Sources & references
2026-09-26 review of open VHS issue #708, current VideoCombine byte path and English wording. The reporter supplied the measurements; no site-run audio, GPU or fix verification is claimed.
01VHS audio dtype report under fp16 intermediatesSource checked: 2026-09-2602VideoHelperSuite READMESource checked: 2026-09-2603VideoHelperSuite sourceSource checked: 2026-09-26