Avidemux Forum

Re-bonjour za tous !

Je cherche à re-dimensionner une vidéo, avec AVI-Demux Nightly et le codec AV1.

Ma vidéo, est encodée par erreur en AV1 : 16/9 : 1920/1080 pix
Je dois la ré-encoder en AV1 : 2,35 non-anamorphique

Calcul de la hauteur : 1920/2,35 ≈ 817,02 pix

Dois-je arrondir ce 817,02 pix au prochain multiple de 2 → 818 pix

Ou, du fait que le plus petit block utilisé par le codec AV1 fait 4/4 pix
Dois-je arrondir ce 1381,29 pix au prochain multiple de 4 → 816 pix

Re-merci d'avance.

Bonjour za tous !

Je cherche à comprendre 2 options liées au codec x264.

Sortie vidéo : MPEG4 AVC (x264)
Configurer : General → Zero latency
Configurer : Output 1 → BluRay compatibility

Quel sont leurs impacts sur la qualité de la vidéo en sortie ?

Merci d'avance.

Quote from: jimmy on October 11, 2026, 01:10:30 AMI shall stick with Sep 12 for now.

I don't think that going back from FFmpeg 9.0.2 to FFmpeg 7.0.2 is a sound strategy, at least as long as disabling AVX/AVX2 is enough to work around the crashes.

Totally agree. Unfortunately Avidemux is so limiting in advanced features, like x265 sao, and lack of hw encoding. unfortunately I didn't find a good alternative for easy cutting, using filters, and encode purpose in Linux.

Quote from: eumagga0x2a on October 10, 2026, 02:11:38 PM

Quote from: Rainman74 on October 10, 2026, 12:43:03 PMWith the current nightly build, the error message no longer appears; instead, the app crashes and freezes.

This is https://avidemux.org/smif/index.php?msg=98711, related to the libavcodec-based AC3 encoder. NVENC-based video encoders are working for you now, aren't they?

Yes, I can confirm, without AVX and AVX2 for AC3 audio, I can encode nvenc HEVC again with the current nightly build!

Please excuse the multiple addendums:
I am currently in the middle of fine-tuning the optimal encoding pipeline specifically for digitized analog media (Hi8, S-VHS, Video8, VHS), which requires tens of tests and constantly brings to light additional critical parameters currently omitted from the Avidemux GUI.

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7. Chroma QP Offsets (cbqpoffs & crqpoffs)

• Current limitation: Completely missing from the Avidemux GUI.

• The issue: Analog tape chroma channels carry heavy phase noise and cross-color bleeding. Standard x265 settings create soft, blotchy patches in dark/noisy scenes.

• The fix: Using negative offsets (cbqpoffs=-2:crqpoffs=-2) allocates finer quantization to Cb/Cr, restoring micro-edge sharpness (e.g. wall textures) without blowing up global luma bitrate.

• Corresponding FFmpeg / x265 CLI parameters:
-x265-params cbqpoffs=-2:crqpoffs=-2

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Food for thought for the devs:

Avidemux is great, but hiding advanced encoder options just to keep the GUI simple degrades the potential of the underlying encoders in general. Exposing parameters like cbqpoffs and crqpoffs in the configuration dialog, or simply enabling a GUI-based custom parameter pass-through string field (e.g., persisted in Hi8-x265.json), would perfectly solve this for archival workflows without cluttering the UI.

Best regards,
Manfred

Ah, too late. Oct 09 nightly, AVX and AVX2 enabled...

Two tests, two different files, freeze-up both times.

I shall stick with Sep 12 for now.

Quote from: Rainman74 on October 10, 2026, 12:43:03 PMWith the current nightly build, the error message no longer appears; instead, the app crashes and freezes.

This is https://avidemux.org/smif/index.php?msg=98711, related to the libavcodec-based AC3 encoder. NVENC-based video encoders are working for you now, aren't they?

Quote from: eumagga0x2a on October 09, 2026, 06:25:32 AMPlease try the 20261009 nightly from https://avidemux.org/nightly/win64/ without this workaround (i.e. with AVX and AVX2 enabled) and report back whether the tentative fix resolves the issue for you, thanks.

I retract my request, for some unclear reason libavcodec AC3 encoder in my local build didn't crash with that patch a few times in a row. The "fix" hasn't solved the issue, unfortunately. Therefore disabling AVX and AVX2 is still required.

Quote from: eumagga0x2a on October 02, 2026, 06:24:54 PM

Quote from: Rainman74 on October 02, 2026, 09:04:45 AMSince avidemux_mingw64_20260912 & 20260922, the nvenc encoders no longer work and throw an error.

May be related to graphics drivers being too old, in doubt please reproduce the issue, close Avidemux and provide admlog.txt from %localappdata%\avidemux directory.

With the current nightly build, the error message no longer appears; instead, the app crashes and freezes.

Here are all the logs: https://pixeldrain.com/u/HbLohN4k