[Ffmpeg-devel-irc] ffmpeg.log.20190815

[burek]

[00:01:01 CEST] <Classsic> I read this https://trac.ffmpeg.org/wiki/Hardware/QuickSync  but can´t find any example like this "ffmpeg -hwaccel vaapi -hwaccel_output_format vaapi ... -i interlaced_input.mp4 -vf 'deinterlace_vaapi,scale_vaapi=w=1280:h=720,hwdownload,format=nv12' -c:v libx264 ... progressive_output.mp4
[00:38:43 CEST] <petecouture> BtbN It worked! thanks again mate. You have a patron account?
[00:38:52 CEST] <BtbN> no
[00:39:11 CEST] <petecouture> Accept donations?
[02:24:38 CEST] <AiNA_TE> hello
[02:24:56 CEST] <AiNA_TE> i am trying to encode on the fly from a directshow device
[02:25:13 CEST] <AiNA_TE> ffmpe is giving me "Interger division by zero." errors
[02:31:11 CEST] <AiNA_TE> https://pastebin.com/raw/iMnFLp1v
[02:32:56 CEST] <AiNA_TE> https://i.imgur.com/H8eUtiK.png
[02:33:09 CEST] <AiNA_TE> this is the crash error
[02:33:15 CEST] <AiNA_TE> anyone know whats up
[02:56:59 CEST] <durandal_1707> the image is blurer
[20:30:59 CEST] <doughy1> why does doing this? ffmpeg -i input1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts output.ts   create 4gig file to 6 gig
[20:34:57 CEST] <furq> what does the last line of the ffmpeg output say under "muxing overhead"
[20:35:52 CEST] <doughy1> furq are you talking to me?
[20:36:11 CEST] <furq> yes
[20:36:31 CEST] <doughy1> i closed the box
[20:36:41 CEST] <doughy1> so i missed it
[20:36:56 CEST] <pink_mist> then reopen it, rerun the command, and check it
[20:37:07 CEST] <doughy1> i deleted input1.mp4
[20:37:14 CEST] <doughy1> i still haved output.ts
[20:37:33 CEST] Action: zeromind sighs
[20:38:02 CEST] <furq> well yeah mpegts has a lot of overhead compared to mp4
[20:38:10 CEST] <furq> 2GB on a 4GB file sounds like too much but shrug
[20:38:17 CEST] <furq> you'd normally expect ~10% overhead or so
[20:38:39 CEST] <doughy1> i ran that command in the first place because it's 2 hour input.mp4 video and but video show duration has 3 hours  and  output.ts has fixed this duration
[20:39:34 CEST] <doughy1> but that also means if i convert  output.ts to  ouput.mp4  it should go back to 4 gigs but it does not
[20:41:43 CEST] <pink_mist> presumably whatever your -bsf:v argument did is a cause then
[20:41:50 CEST] <pink_mist> since that's the only other variable you have
[20:42:06 CEST] <doughy1> what does bsf-v do
[20:42:20 CEST] <furq> it isn't
[20:42:23 CEST] <pink_mist> no idea, why did you put it in your commandline?
[20:42:36 CEST] <furq> that bsf gets autoinserted for mp4 to ts in recent ffmpeg
[20:42:53 CEST] <pink_mist> huh, ok
[20:42:56 CEST] <doughy1> because this help page says so:  https://trac.ffmpeg.org/wiki/Concatenate#differentcodec
[20:44:13 CEST] <furq> that doesn't add a significant amount of data and it'll be reversed when going back to mp4 anyway
[20:45:27 CEST] <furq> annex b should be slightly smaller than avcc if anything
[20:45:41 CEST] <furq> but very slightly
[20:47:37 CEST] <pink_mist> doughy1: well, without the original file, it would be my guess that it's impossible to figure this out
[22:57:07 CEST] <firelegend> Hi all. I would like to ask about dav files, whether the format has been documented somewhere?
[22:57:50 CEST] <durandal_1707> firelegend: be more specific
[22:58:12 CEST] <durandal_1707> do you mean dahua cctv stuff?
[22:58:49 CEST] <firelegend> Yes
[22:59:01 CEST] <firelegend> I see that ffmpeg supports decoding the format
[22:59:26 CEST] <durandal_1707> everything is documented in dhav demuxer
[23:00:02 CEST] <durandal_1707> just because it may have also audio
[23:00:21 CEST] <firelegend> Relevant part? https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/dhav.c
[23:00:28 CEST] <durandal_1707> yes
[23:01:00 CEST] <durandal_1707> why are you interested in that format?
[23:01:18 CEST] <firelegend> Because it's obscure
[23:01:46 CEST] <firelegend> I even busted out ghidra and x64dbg ready to dig into the proprietary code
[23:02:02 CEST] <firelegend> but if it's been implemented it will help me
[23:02:21 CEST] <durandal_1707> feel free to improve it more
[23:02:35 CEST] <durandal_1707> it was also REd
[23:02:57 CEST] <firelegend> I'd imagine so, RE is a fun subject.
[23:03:07 CEST] <firelegend> But I am glad someone has already done the heavy lifting :)
[23:04:37 CEST] <durandal_1707> it was done with limited number of samples,  format appears to support more obscure codecs
[23:05:06 CEST] <firelegend> Obscure as in fully in-house
[23:05:11 CEST] <firelegend> or modified existing codecs.
[23:05:43 CEST] <durandal_1707> all codecs it use are normal existing codecs
[23:06:32 CEST] <firelegend> So they just insert more metadata and different header\?
[23:07:36 CEST] <durandal_1707> appears so
[23:10:12 CEST] <firelegend> Is there any reason for them to use modified codecs and not whats publicly available?
[23:11:17 CEST] <durandal_1707> it use unmodified codecs in own clumsy container
[00:00:00 CEST] --- Fri Aug 16 2019