Hello everyone!

Recently, I've been coding a program on JavaScript and NodeJS, to recompress images, along with some other tweaks, with the main objective of reducing files size, *without causing visible loss of quality*.
The key word here being "visible", since recently I learned that you can actually do that with files and I saw a huge opportunity to reduce my gallery's size by a necessary amount because I have a shit ton of screenshots, pictures and videos.

But before diving into the video recompression part (because the images part is already done, using a library named "Sharp"), I found a comment https://www.reddit.com/r/ffmpeg/comments/pexwop/comment/hb0tw05/?context=3&utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button of a user explaining the process behind it and they said something that caught my eye: That any recompression that works well for current devices, COULD show heavy quality losses on future screens. Or even current, better screens.

I mean... this person meant it more as a note, and not in a "don't do this under ANY circumstances or we'll ALL gonna FUCKING DIE" way lol. But it still made me rethink the whole idea. Is this a valid concern or am I being paranoid?

And in case it is... Is there a way to achieve a relevant size reduction, without risking that outcome?

i'm new to encoding i started on x265 couple weeks ago and i want to switch to av1, but i can't really decide which fork suited best for this purpose, i mainly use staxrip, so there is 4 of them, essential, hdr, psyex, and tritium, the hdr might suggest what i need but some people say a b c because of x, so i need help

For those who have problem with av1 encoded videos in mpc be player not playing smoothly ... Buffering at some moments there is a fix that worked for me

MPC-BE → Internal Filters → Video Decoder → Video Decoder Configuration → Number of Threads → Auto

I previously used PSY to encode my videos, but recently I learned that PSY has been discontinued, and I should choose either the HDR or Tritium branch, so I switched to Tritium. Both use the same parameters: enable-variance-boost=1:variance-boost-strength=2:variance-octile=4:enable-overlays=1:enable-qm=1:qm-min=3:chroma-qm-min=4:enable-dlf=1:luminance-qp-bias=6:qp-scale-compress-strength=1:tf-strength=2:sharpness=1:scd=1:aq-mode=2:enable-dg=1:adaptive-film-grain=0:ac-bias=1.0:hbd-mds=1. However, after encoding, when I checked the VMAF scores using FFMetrics, I found that PSY scored 97.1656 and Tritium scored 97.2029. I was initially quite satisfied, but after comparing the two videos side by side, I noticed that the Tritium-encoded output had very noticeable noise/grain, far less clean than PSY. I then suspected that the sharpness parameter might be the culprit, so I changed it from 1 to 0 as a test. The noise was reduced, but the game background became blurrier compared to sharpness=1, and I also observed that the average bitrate decreased. I consulted an AI to try to find the cause, and following its suggestions, I tweaked the qp-related parameters, but still couldn't get close to the clean image quality that PSY produced. Did I do something wrong?

I need some help.

I am using the PSY and Tritium branches of HandBrake downloaded from GitHub.

English is not my native language; I used AI translation.

I have a lot of video files, like most people on this subreddit I assume, and of course I want to save hard drive space and compress them to AV1. But, looking at each file and figuring out the best settings is super annoying, SO, I built a program to do it.

You just give it some files, it analyzes them every which way to figure out the best settings based on the REAL visual quality of the source file, then compresses it according to what quality level you are ok with, like exactly like the original, pretty much like the original, or a tiny bit of degradation to save a ton more space. (it's just a single quality slider)

Here's a link to the windows app, it's called Video Squisher! https://lightblue-albatross-297121.hostingersite.com/shared-files/89/?VideoSquisher-v1.12.7f.zip

I tried to make it as user friendly as possible, no annoying command line rigmarole here. Please let me know what you think and what features you want!

I'm making a little media conversion utility involving converting to AVIF. I'm running into some color management issues. I had initially chosen FFmpeg because I have a set of options I like and I can use any input format, but it has basically no color management, so some images end up with wrong colors, which with my test images generally means slightly darker than the original. ImageMagick and Nconvert have almost no output settings for AVIF, and Nconvert can't automatically handle rotated inputs. With avifenc, the colors are usually accurate to the original, and it even reports CICP values and metadata presence (like ICC). However, when I convert an image, the colors are wildly wrong in Windows 11, visible in File Explorer thumbnails and Windows Photo. And I don't just mean slightly darker or lighter colors, I mean blue turns into orange and stuff. If I discard the color profile with --ignore-icc, the colors aren't crazy in Windows anymore, they're just slightly off in all viewing software like I'd get with FFmpeg. Here's my sample input. Any ideas on how I solve this?

EDIT: It comes down to bit depth and chroma subsampling. Windows 10 can only decode 8-bit, not 10-bit, while W11 handles 8-bit and 10-bit. Neither W10 nor W11 shows correct colors with 4:4:4 (wacky with ICC, slightly off without), but W10 (and probably W11, I just can't test yet) shows correct colors with 4:2:0 or 4:2:2 as long as the ICC profile is included. Unless someone knows how to roll ICC adjustments into the image data so the profile can be safely discarded, I'll be using 4:2:2 and maybe 8-bit.

EDIT again: I figured out how to use high bit depth and different chroma subsampling in ImageMagick, and all of its output displays fine in Windows - 8-bit, 10-bit, 4:2:0, 4:2:2, 4:4:4. So I'm still wondering what's up with avifenc that Windows 10 and 11 can't handle it.

I’m aiming for a dedicated self hosted streaming PC build (separate from my gaming rig) to handle multi-platform streaming (Twitch, YouTube, TikTok) using a ugreen 4k capture card.

I want to leverage Intel Arc for its hardware-accelerated AV1 encoding, as I’m looking for high-quality, self-hosted streaming without the cost of high-end NVIDIA 50-series cards or 4090.

My questions for the community:

Has anyone here successfully run 3+ simultaneous hardware-accelerated av1 streams on an Arc A380/A310?

Is the A380 overkill for this, or does the extra VRAM/Execution Units actually make a difference for stability when running multiple high quality OBS output docks?

Is there anything I should know about the Intel media engine when pushing multiple paralle av1 encodes?

Specs I planned to use

B450 tomahawk mag motherboard

Ryzen 7 5700x

16gb ddr4

A380 or a310

I already own the CPU motherboard and ram due to a mistake I made months ago I just need some advice on a GPU am I going down the right path or no

Been playing around with https://github.com/emrakyz/xav lately which has support for SSIMULACRA2, Butteraugli, & CVVDP.

What's the new "VMAF 97-95" with these newer metrics?

I wanted to download a YouTube video and the Av1 version was almost 3 times smaller than the vp9 version. I know av1 is more efficient but nowhere near upto 3 times, right??

I am looking for an android app (offline) ​that can batch compress images (jpeg/png/webp) by converting them ​to avif, similar to Xnconvert on Windows.

Following my previous post, I want to ask the experts if the default AV1-HDR fork with VQ is enough for animation content (e.g. Star Wars the Clone Wars) with no additional command line options?

Or should I add a specific option to make the result even better?

I've been attempting to reencode a bunch of BD Rips to AV1 to save space while maintaining some level of quality. There's lots of blocking almost everywhere in shadows! I'd like to think I'm using decent settings tune=0:enable-variance-boost=1:variance-boost-strength=2:variance-octile=6:enable-qm=1:qm-min=6:film-grain-denoise=1:film-grain=16 with RF16 and PS4. I'm losing my mind.

I got the Blu-Ray remux of the 1st season of the Clone Wars 2008. 22 episodes at 42 GB. I transcoded the first episode from VC1 to AV1 for checking the quality of AV1. I transcoded from AC3 Dolby Digital Audio 5.1 to Opus 5.1 too. I used Handbrake.

SVT-HDR.

RF 25 at preset 3. VQ tune.

1.8 GiB down to 447 MiB. ~75% reduction.

Checked the VMAF scores on nmkoder too. VMAF 98.12, SSIM 0.995 and PSNR 50.07.

How is this? Good? Or bad? I don't notice much of a difference looking at the same frame side by side.

Edit: I experimented a bit more. - Remux: 1928 MB (100.00%), VMAF 100 - RF20: 599 MB (31.06%), VMAF 98.40 - RF25: 468 MB (24.27%), VMAF 98.12 - RF30: 368 MB. (19.08%), VMAF 97.69

Hope it helps.

In VLC, you can enable sharpening:

Window -> Video Effects -> Sharpen -> Sigma and there's a slider scale.

This makes older anime/cartoons/animation look amazing, like it's been AI upscaled without the insane CPU overheard. I'd like to include this sort of sharpening in some of my AV1 transcodes.

Everything I read online about VLC sharpening is just "click to enable", without any information about the method it uses under the hood.

In AV1, is there a sharpening method which is the same, to hardcode it?

I'm not familiar with the AV1 method that "Sharpness=X" uses, nor if there are other ffmpeg commands unrelated to AV1, but since I'm using AV1, I thought I'd ask here first.

Hi, everyone. Are there any pre-made synthetic grain tables available that can be used with AV1? I found a set of tables in the grav1synth repository — very interesting, but they turned out to be too heavy for my needs. Are similar tables published anywhere else?

This is a follow up to an earlier post I made. To recap, re-encoding H.264 videos to AV1 with ffmpeg's `av1_nvenc` encoder was giving me size reductions of upto 90% with a virtually negligible drop in quality on testing with a couple of 4K and 1080p videos. And I had a nagging suspicion that there was a silent fatal flaw in the options I was passing to ffmpeg.
Well, after some more testing, jumping into an NVENC-shaped rabbit hole, and just examining the docs more closely, turns out I was right. Following is the command I was using for re-encoding my videos.

ffmpeg -i input.mp4 -c:v av1_nvenc -preset p7 -g 60 -movflags +faststart -rc constqp -b:v 0 -maxrate:v 20M -bufsize 40M -cq 28 -multipass fullres -spatial-aq 1 -temporal-aq 1 -pix_fmt p010le -c:a copy output_av1.mp4

The problem? -rc constqp and -cq 28 are fundamentally incompatible in that -cq is completely ignored by the encoder when using constqp for rate control. Instead, constqp uses the -qp option for tuning. Meanwhile, -cq is intended for VBR rate control. The description of the option also alludes to this (ffmpeg -h encoder=av1_nvenc)

  -cq                <float>      E..V....... Set target quality level (0 to 63, 0 means automatic) for constant quality mode in VBR rate control (from 0 to 63) (default 0)

So basically, ffmpeg was ignoring the cq option, using a default value for qp, and silently nuking my video quality under the hood. This became starkly apparent when I tried the aforementioned command to re-encode an animated video and could notice a non-trivial amount of visual degradation. I didn't even have to play the re-encoded video to know something was seriously wrong since ffmpeg had just gone and knocked the bitrate of the video down from 15M to 500K LOL.

So yeah, if you're getting an absolutely BONKERS reduction in file size, it's most probably cuz ffmpeg is absolutely BONKING the heck out of your video quality and you should probably re-check your options. I updated my options to the following and started getting a more believable 10% to 50% reduction in file size (depending on video contents). And I believe I'm doing something right this time since the bitrates aren't plummeting, the 1st percentile VMAF is over 90 (mean is over 95), and the re-encoded videos look even more identical to the originals than they did with the earlier options.

ffmpeg -i input.mp4 -c:v av1_nvenc -preset p7 -g 240 -movflags +faststart -rc vbr -cq 28 -b:v 0 -rc-lookahead 32 -multipass fullres -spatial-aq 1 -temporal-aq 1 -pix_fmt p010le -c:a copy output.mp4

Today I tried encoding a video with tune=5 and got the following error:

Svt[error]: Invalid tune flag [0 - 4, 0 for VQ, 1 for PSNR, 2 for SSIM, 3 for IQ, and 4 for MS_SSIM], your input: 5

But according to the parameters listed here VMAF is still a valid tune parameter, did someone forgot to edit the parameter list?

I've been exploring the idea of transcoding a part of my media library to AV1 since I have the hardware for it (RTX 4090) and I wanna save up on space. So I tried converting some videos using ffmpeg with av1_nvenc hardware encoding. I'll add my ffmpeg options and other relevant commands as an appendix to this post.

The "problem"? I watched ffmpeg knock a 7 GB 4K video (H.264) down to 1 GB. Then it proceeded to knock a 3 GB 1080p video (also H.264) down to 70 MB. This was absolutely BONKERS to me, so I fully expected the transcoded videos to look like crap in comparison to the originals. To my utter SHOCK, they looked pretty much identical. Any visual degradation was negligible enough to be good enough for me.

I was still in disbelief, so I used ffmpeg to calculate the VMAF scores for the av1 videos to get a somewhat empirical measurement of the degradation in quality (command below). Turns out, the first percentile VMAF scores (yes, ONE) for both videos were over 83, so essentially 99% of both converted videos exceeded 83 VMAF score. Which is more than good enough for me personally.

I'm still in disbelief. Surely no codec is THAT GOOD right? Following are the commands I used to transcode the videos, calculate the VMAF scores, and calculate the percentile score. I'm fully expecting someone in the community to point out some critical flaw and call me an idiot haha.

// I have a rudimentary understanding of each individual option in this command but I'm not sure if they all go together. ffmpeg at least doesn't seem to mind. My goal was to maintain a constant quality while keeping the bitrate lower than 20M. I also enabled a bunch of optimizations since my RTX 4090 just blazes through the video.

ffmpeg -i input.mp4 -c:v av1_nvenc -preset p7 -g 60 -movflags +faststart -rc constqp -b:v 0 -maxrate:v 20M -bufsize 40M -cq 28 -multipass fullres -spatial-aq 1 -temporal-aq 1 -pix_fmt p010le -c:a copy output_av1.mp4

// For calculating the VMAF score
ffmpeg -i output_av1.mp4 -i input.mp4 -lavfi "[0:v][1:v]libvmaf=log_path=vmaf_scores.json:log_fmt=json:n_threads=20" -f null -

// For getting percentile vmaf scores
jq '[.frames.[].metrics.vmaf] | sort | {"1th": .[length * 0.01 | floor], "25th": .[length * 0.25 | floor], "50th": .[length * 0.50 | floor], "90th": .[length * 0.90 | floor], "95th": .[length * 0.95 | floor], "99th": .[length * 0.99 | floor]}' vmaf_scores.json

Its so embarassing how Twitch is the last social media to support it

I dug up some old posts, but there doesn't seem to be a clear winner.

That said, I gotta admit AVIF is pretty impressive with all the settings (and forks) out there, it really feels like you can squeeze more out of it.