03:18 <FH_thecat> I have mp4 video file, just few seconds long but it is 90MB. How can I make it smaller, under 10MB, perhaps by increasing compression, lower bitrate, or fewer frames?

03:18 <FH_thecat> or perhaps how can I create animated gif from it?

03:19 <FH_thecat> it is recording of my screen, so the rate per second can set quite low

04:09 <aaabbb> FH_thecat: you'd want to use a slow preset

04:11 <aaabbb> ffmpeg -i in.mp4 -c:v libx265 -preset slower -crf 28 -g 600 -tag:v hvc1 -c:a copy out.mp4

04:11 <aaabbb> at a minimum, adjust crf to your liking

04:12 <aaabbb> FH_thecat: what's the resolution? are you fine with a lower resolution?

05:18 <FH_thecat> aaabbb: thank you, that reduced the size from 90MB to 8MB, with good quality

05:23 <aaabbb> FH_thecat: you're welcome. using an even slower preset can (slightly) increase quality, and you can use crf to adjust birate (higher = lower bitrate)

05:43 <aaabbb> also, doing -pix_fmt yuv420p10le increases compression too, but makes playback more resource-intesive

10:29 <jpsollie> hello everyone, I'm trying to setup a NAS where my mobile phones can be backed up (images, videos etc), and automatically verified on sync. For the verification, I found the following command to work properly:

10:29 <jpsollie> ffmpeg -err_detect explode -i "$i" -c:v rawvideo -c:a anull -f null - >/dev/null 2>&1;

10:29 <jpsollie> so far so good, but this takes a lot of CPU

10:30 <jpsollie> I have an amdgpu GPU built-in which should be able to do basic h264 decoding to see whether the image is valid

10:30 <jpsollie> but it fails with the error: "Codec h264 profile 66 not supported for hardware decode."

10:31 <jpsollie> ffmpeg -v warning -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -i janpieter/2023-12-02-14-56-18-702.mp4 -c:v rawvideo -c:a anull -f null /dev/null

10:31 <jpsollie> vainfo shows: VAProfileH264ConstrainedBaseline: VAEntrypointVLD

10:32 <jpsollie> so, why is it not possible?

10:32 <jpsollie> and if possible, can I mark it as a main profile and let the vaapi decoder try to decode it anyway?

10:33 <jpsollie> VAProfileH264ConstrainedBaseline: VAEntrypointVLD

10:33 <jpsollie> VAProfileH264Main : VAEntrypointVLD

10:33 <jpsollie> VAProfileH264High : VAEntrypointVLD

10:33 <jpsollie> it would be nice if GPU offloading could be used here ...

10:52 <BtbN> Well, the error seems quite clear

10:52 <BtbN> The video is using too high of a profile that the hardware decoder does not support

10:54 <jpsollie> yes, but can I instead decode it as a main profile?

10:55 <jpsollie> I mean, mpv (which mostly works using ffmpeg's libs) has a vd-lavc-check-hw-profile switch

10:55 <jpsollie> how do I do that using plain ffmpeg?

11:01 <jpsollie> https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/vaapi_decode.c <-- the vaapi profile map doesn't even list baseline profile here, so there should be a way to override it

13:53 <CounterPillow> That's because baseline profile is not a strict subset of main, and constrainedbaseline was made as a "mea culpa" to fix that situation. It's rare to see baseline actually used.

13:53 <CounterPillow> You can't decode baseline with main profile I'm pretty sure because that's the entire issue with that original baseline profile spec, it's not a subset.

19:13 <Epakai> I have some inogeni usb capture devices. On first record they give a start_time value, but subsequent ones give 0 so there is a large offset (often several hours) between the video start and first frame. Can I fix that at capture time?

19:14 <Epakai> I have been working around by running usbreset on the device, but that's slow, or just recopy the video stream after.

19:17 <kepstin> is this video only, or video and audio?

19:17 <Epakai> both

19:18 <kepstin> hmm. i'm not sure what the best way to do that while keeping both in sync would be :(

19:41 <Epakai> video only would be useful too. I tried -copyts, and there even the first capture has the large offset. -start_at_zero, and -ss don't seem to have effect

19:43 <kepstin> what input format is this? v4l2?

19:45 <kepstin> for video frames, you could try adding "-vf setpts=PTS-STARTPTS" to subtract the value of the first-seen timestamp from all timestamps, which should remove the offset.

19:51 <Epakai> yeah, v4l2. that is effective

21:45 <bcn_> ffmpeg is barfing while trying to concatenate large numbers of wyzecam video files. didn't used to do this: https://paste.centos.org/view/e5ec614a the file list shows no oddness. the files are there, and all about the same size. it barfs at the same time repeatably. and it's not BETWEEN input files either. its mid file the same file each time. Is there an integrity test I could run on each input file to check if its good before adding it to the list?

21:52 <bcn_> it's not just one input file either, several. probably 2% of them, and so far I'm just removing each from the list and trying again.. grrr