June 2019 - Ffmpeg-devel-irc - lists.ffmpeg.org

ffmpeg-devel.log.20190601
by burek 02 Jun '19

02 Jun '19

[03:46:36 CEST] <nkk> FFmpeg stops output whenever there is concealing error (or) circular buffer overflow [03:46:46 CEST] <nkk> can anyone please help me [10:14:17 CEST] <pross> durandal_1707: how is the new siren decoder? [10:40:58 CEST] <durandal_1707> pross: nowhere due to very positive reviews [11:44:08 CEST] <cone-038> ffmpeg 03Steven Liu 07master:76ef18fd3910: avutil/dynarry.h: fix comment grammar mistakes of FF_DYNARRAY_ADD [13:00:58 CEST] <mkver> cehoyos: What do you think of my newest verson of the hcom patch? [13:09:17 CEST] <cehoyos> I don't think it is as readable as "/* data_size = */ avio_rb32(s->pb);" or "avio_skip() /* data_size*/" (and I don't see while read_header() has to be optimized) but others may disagree [13:09:33 CEST] <cehoyos> s/while/why [14:46:10 CEST] <vtorri99978666> hello [14:46:48 CEST] <vtorri99978666> i have cross compiled ffmpeg, targetting Windows, and i see several warnings about deprecated functions which are used [14:47:03 CEST] <JEEB> if it's stuff within the FFmpeg repo itself, it's OK [14:47:07 CEST] <vtorri99978666> are you interested in the complete log ? [14:47:27 CEST] <JEEB> I mean, we know there are some parts still using deprecated things, but those will get fixed/removed after the deprecation period ends [14:47:32 CEST] <JEEB> because otherwise it would not build [14:48:50 CEST] <vtorri99978666> ha, ok [14:49:00 CEST] <vtorri99978666> i understand [14:51:26 CEST] <vtorri99978666> there are other warnings [14:51:45 CEST] <vtorri99978666> %s format not known, or warning about signed oeverflow [14:52:14 CEST] <vtorri99978666> comparison of unsigned with < 0 [14:52:56 CEST] <vtorri99978666> array subscript beyond array bounds [14:55:14 CEST] <cehoyos> vtorri99978666: Where is the comparison of unsigned with <0? [14:55:20 CEST] <cehoyos> The array subscript is a gcc bug [14:55:59 CEST] <JEEB> I think the %s format thing is a problem in hlsenc I think? some weird ifdef in there [14:59:40 CEST] <vtorri99978666> JEEB exactly [14:59:52 CEST] <vtorri99978666> cehoyos yes [15:00:23 CEST] <cehoyos> The comparison is in yes? [15:05:12 CEST] <vtorri99978666> fds[i].fd < 0 [15:05:15 CEST] <vtorri99978666> cehoyos ^ [15:05:41 CEST] <cehoyos> Would you like to tell me the filename? [15:06:16 CEST] <vtorri99978666> more annoying : x86_64-w64-mingw32-nm fails : file format not recognized [15:06:50 CEST] <vtorri99978666> libavformat/os_support.c [15:06:53 CEST] <vtorri99978666> cehoyos^ [15:07:59 CEST] <vtorri99978666> cehoyos line 248 [15:08:43 CEST] <cehoyos> fd is signed here, so I don't think this can be fixed [15:17:16 CEST] <mkver> It could be fixed with #ifdefs if one knew exactly the systems for which fd is unsigned. [15:19:35 CEST] <cehoyos> Sounds like a bad idea (not because of the ifdefs) [15:21:07 CEST] <mkver> And why? [15:23:42 CEST] <cehoyos> How would you know? [15:25:00 CEST] <mkver> Maybe it is documented for these systems? [15:25:31 CEST] <mkver> If it is not, then the approach is not feasible. [16:13:57 CEST] <vtorri99978666> i don't know if some people are cross-compiling ffmpeg with minw-w64 but on my computer, it is working [16:14:01 CEST] <vtorri99978666> just fyi [16:14:23 CEST] <JEEB> yea I think we have that in FATE [16:14:39 CEST] <JEEB> and I do it periodically to test my own patches and mpv etc [16:15:01 CEST] <JEEB> http://fate.ffmpeg.org/ [16:15:05 CEST] <JEEB> you can ctrl+F mingw there [16:15:27 CEST] <JEEB> there are both 32bit and 64bit builds being done [16:25:48 CEST] <vtorri99978666> and with how many external libraries ? [17:21:11 CEST] <adrian_> anyone has experience compiling ffmpeg with clang before ? how does O3 performance compare to gcc ? I also tried ./configure --cc=clang --cxx=clang++ --enable-lto and it did not work. [17:21:15 CEST] <adrian_> thanks ! [17:23:19 CEST] <cehoyos> wrong channel [17:23:35 CEST] <adrian_> what is the right channel ? thanks [17:23:55 CEST] <cehoyos> "using" in the channel title includes "building" [17:26:12 CEST] <adrian_> there are devel and non-devel channel [17:26:21 CEST] <adrian_> do you suggest i go ask in the non-devel channel [18:46:14 CEST] <JEEB> anyone here with FFmpeg built with gnutls? seems like we're failing at TLS with facebook [18:47:20 CEST] <JEEB> so if you get a URL through f.ex. youtube-dl (f.ex "https://www.facebook.com/downshiftaus/videos/418766325569703/" was posted to me as an example), and then try opening it through lavf it seems to fail? [18:47:48 CEST] <JEEB> open/libressl seems to work [18:48:38 CEST] <JEEB> got a report that it works with the same gnutls through wget so it's likely to be in our TLS wrapper [18:48:47 CEST] <JEEB> (if someone else can replicate it) [19:01:43 CEST] <nevcairiel> i think i saw a patch for that [19:02:03 CEST] <JEEB> ah [19:02:11 CEST] <nevcairiel> https://patchwork.ffmpeg.org/patch/12492/ this probably [19:02:56 CEST] <JEEB> cheers, will have it tested :) [19:03:12 CEST] <nevcairiel> i should probably pick that as well [19:05:20 CEST] <JEEB> > my wireshark cap shows that mpv terminates the connection right after it tries to change the cipher suite so this patch seems to be applicable to this situation [19:05:39 CEST] <JEEB> so it seems like cipher suite reneg is one of those error cases [19:29:35 CEST] <JEEB> nevcairiel: I can verify that patch fixes the issue [19:30:02 CEST] <JEEB> -33 [19:30:20 CEST] <JEEB> > I just tested with badssl and it does correctly bail out with e.g. ./ffplay https://rc4.badssl.com/ [19:30:42 CEST] <JEEB> and that seems to be a fatal error so it seems like the patch's OK [19:34:20 CEST] <durandal_1707> than kindly reply with LGTM [19:35:50 CEST] <JEEB> yea, I am writing it down atm [19:39:00 CEST] <JEEB> there [19:42:27 CEST] <JEEB> I'll let people look at it a bit and possibly respond, and if there are no further comments I'll at least pull it into master since the loop more or less looks OK to me [19:57:58 CEST] <cone-038> ffmpeg 03Marton Balint 07master:415886588fad: doc/filters: move reference to framesync options from lut3d to haldclut [20:15:07 CEST] <JEEB> durandal_1707: btw have you checked what sort of threading makes sense with zscale? since I think as soon as the slices become smaller the perf benefits get smaller (if at all)? [20:15:42 CEST] <JEEB> as in, should the amount of slices be limited by a minimum height per slice [20:16:31 CEST] <durandal_1707> width [00:00:00 CEST] --- Sun Jun 2 2019

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ffmpeg.log.20190601
by burek 02 Jun '19

02 Jun '19

[00:54:06 CEST] <aruns> Hi there, I have a quick question: when using FFMPEG to reduce a file size of a video, say an MP4, while maintaining enough quality, I was thinking that I could divide the bitrate by 100 and then multiplying it by the desired percentage. [00:54:22 CEST] <aruns> Is there a target percentage I should aim towards? [01:12:06 CEST] <kepstin> aruns: you can encode to any size you like by setting a bitrate - whether it "maintains enough quality" depends on a bunch of encoding options (preset in particular, with libx264), and can only really be judged with your eyes [01:12:40 CEST] <kepstin> aruns: for most use cases I recommend using the -crf option with libx264 to set the desired quality level, and then the encoder will make the video as small as it can while maintaining that. [01:18:42 CEST] <aruns_> Ah OK, thanks kepstin [01:19:10 CEST] <aruns_> kepstin: So something like the following should be OK: ffmpeg -i input.mp4 -c:v libx264 -crf 28 -preset slow -c:a copy output.mp4 [01:21:01 CEST] <kepstin> Yeah, but -crf 28 looks pretty bad. Try a few values on short clips to see what you like. [01:21:37 CEST] <kepstin> Lower numbers are higher quality, default is 23 [01:24:11 CEST] <aruns_> The original MP4 is about 2.2G [01:24:34 CEST] <aruns_> I am trying to figure out what the ideal size should be, as I want to transfer it to the cloud NAS I have configured at home. [01:24:54 CEST] <aruns_> It's a full movie, so may take a while to convert. [01:25:41 CEST] <aruns_> Thanks, I have the command in place now :) [01:27:08 CEST] <BtbN> The ideal size is however bad you're okay with it looking [01:34:30 CEST] <gentwo> Hi, i am trying to playback a file, ffplay error shows "Could not initialize SDL - No available video device (Did you set the DISPLAY variable?)". gone through couple of options from google but none of them seems to be working . i am on gentoo and all use flags are set porperly. [01:41:27 CEST] <gentwo> username234 echo $DISPLAY shows 0:0 [02:47:16 CEST] <gentwo> problem resolved by rebuilding libsdl2 with alsa support [22:20:00 CEST] <Erasmus> I am on macos mojave have ffmpeg installed with homebrew. I cannot convert a flac file to mp3. [22:20:11 CEST] <Erasmus> I get Illegal instruction: 4. [22:20:19 CEST] <Erasmus> don't know what else to try. [22:20:21 CEST] <Erasmus> help. [22:20:32 CEST] <JEEB> full command line and terminal log with -v verbose at the very least in a pastebin [22:20:35 CEST] <JEEB> then link the pastebin or so here [22:20:43 CEST] <Erasmus> ok [22:21:51 CEST] <Erasmus> https://paste.lowtech.io/?345bb0df37b03f5c#/JQroFjR+gln3vt62y9wM2NjQaDpTp4z… [22:22:22 CEST] <Erasmus> https://paste.lowtech.io/?9ae3e3c87f24047a#kYIUkLR4+X5tu0j0chFBB0gtcUiyxTAY… [22:23:15 CEST] <JEEB> you built that yourself through homebrew right? [22:23:32 CEST] <JEEB> can you install it with disable-stripping and then check out with lldb where it crashes exactly? [22:23:46 CEST] <JEEB> it seems to get far enough where it kind of starts up, but then something borks [22:23:50 CEST] <Erasmus> yes [22:24:03 CEST] <JEEB> so basically --disable-stripping in addition to the other flags [22:24:07 CEST] <JEEB> that should keep debug symbols [22:24:08 CEST] <Erasmus> so unlink and remove it and then what? [22:24:28 CEST] <JEEB> no I mean, just rebuild with the debug symbols included (--disable-stripping) [22:24:37 CEST] <JEEB> then https://lldb.llvm.org/lldb-gdb.html [22:24:50 CEST] <JEEB> then you'll have to poke lldb to execute your command [22:24:56 CEST] <JEEB> and see where it crashes and post the backtrace [22:25:06 CEST] <Erasmus> i don't understand [22:25:43 CEST] <JEEB> to give you any sort of help since I have never seen such an error on macs so far, we'll need a backtrace [22:26:03 CEST] <Erasmus> I used homebrew to install it [22:26:16 CEST] <JEEB> to get a readable backtrace you need to give homebrew's FFmpeg the option --disable-stripping [22:26:18 CEST] <Erasmus> brew install ffmpeg --HEAD [22:26:21 CEST] <JEEB> in addition to the stuff you already have there [22:26:36 CEST] <Erasmus> brew install ffmpeg --HEAD --disable-stripping [22:26:45 CEST] <Erasmus> that? [22:26:55 CEST] <JEEB> no, you'll have to check out homebrew how to add/remove configuration options [22:27:18 CEST] <JEEB> since most likely it will not read additional options from the brew command line like that :P [22:28:32 CEST] <JEEB> sorry, I don't use homebrew myself so I can't tell you how to get it done easily. alternatively, we can try building separately from homebrew if you want :P [22:28:50 CEST] <Erasmus> https://trac.ffmpeg.org/wiki/CompilationGuide/macOS [22:28:53 CEST] <Erasmus> that is what I did. [22:30:04 CEST] <JEEB> that doesn't help you or me. that's just stuff written by someone at some point [22:30:10 CEST] <JEEB> it's not like the wiki is write protected [22:30:23 CEST] <JEEB> and I just don't know homebrew specifically so I will not be of use with homebrew [22:30:59 CEST] <JEEB> in short I have a heavy hunch that your problem is not with FFmpeg itself but something built into it, but to prove that and figure out where the issue lies, we'd have to get a backtrace [22:31:24 CEST] <JEEB> or the configuration specified by that homebrew formula [22:31:28 CEST] <Erasmus> that is what you get when you search homebrew in https://trac.ffmpeg.org/search?q=homebrew [22:32:05 CEST] <JEEB> yes? I mean, that still doesn't help you or me [22:32:14 CEST] <JEEB> I don't know about homebrew and you don't seem to either [22:32:34 CEST] <JEEB> I just know what the next steps would be to seek out answers to your problems :P [22:32:39 CEST] <JEEB> in the context of FFmpeg itself [22:33:31 CEST] <JEEB> of course you can test creating a backtrace with the build you currently have [22:33:41 CEST] <JEEB> but it probably won't have too much use :P [22:33:53 CEST] <JEEB> see the lldb page I linked [22:34:08 CEST] <JEEB> ah, there is also a tutorial for lldb https://lldb.llvm.org/use/tutorial.html [22:34:20 CEST] <JEEB> basically you need to launch ffmpeg under lldb :P [22:35:11 CEST] <JEEB> (also jesus that tutorial is not really a tutorial - the only quickly useful part I can see is the process launching) [22:35:18 CEST] <JEEB> which thankfully is in the beginning [22:36:20 CEST] <JEEB> ok, so backtrace is "bt" in lldb as well :P [22:37:02 CEST] <JEEB> without debug symbols in your FFmpeg build it's not gonna give much but if you really can't figure out how to make homebrew add an option to the FFmpeg configure, then it might be worth a shot to try it with your current one [00:00:00 CEST] --- Sun Jun 2 2019

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ffmpeg-devel.log.20190531
by burek 01 Jun '19

01 Jun '19

[03:58:25 CEST] <krish> Hi need help, ffmpeg stops output whenever there is a concealing (or) circular buffer overrun, [03:58:30 CEST] <krish> can you help me [10:27:22 CEST] <nkk> ffmpeg is outputting frames whenever there is circular buffer overflow [12:54:11 CEST] <cone-868> ffmpeg 03Paul B Mahol 07master:b19550367fff: avfilter: add showspatial multimedia filter [17:15:57 CEST] <JEEB> btw durandal_1707 - have you seen this example in the zimg repo? https://github.com/sekrit-twc/zimg/blob/master/doc/example/tile_example.cpp [17:33:01 CEST] <durandal_1707> JEEB: no, i'm feeling so dumb now, thanks for pointing it for me. [17:33:56 CEST] <JEEB> np. glad to be of use :) [19:17:49 CEST] <cehoyos> durandal_1707: May I remove the two write-only variables from libavfilter/avf_showspatial.c or do you plan to use them in the future? [20:19:52 CEST] <mkver> durandal_1707: Same question as cehoyos, but this time regarding the hcom demuxer. [21:00:09 CEST] <durandal_1707> cehoyos: which variables? [21:05:56 CEST] <durandal_1707> mkver: ask someone to apply it [21:20:58 CEST] <mkver> Do you intend to use these variables in the hcom muxer at all? If not, one could consolidate the avio_skip calls into one call (I didn't think about this when sending my patch). [22:16:45 CEST] <cehoyos> durandal_1707: libavfilter/avf_showspatial.c:157:26: warning: variable w set but not used [22:17:00 CEST] <cehoyos> libavfilter/avf_showspatial.c:157:23: warning: variable h set but not used [22:17:15 CEST] <cehoyos> mkver: I believe the same patch as yours was rejected before. [22:18:46 CEST] <durandal_1707> cehoyos: remove it [22:19:39 CEST] <mkver> Found it: https://ffmpeg.org/pipermail/ffmpeg-devel/2019-January/239072.html [22:21:04 CEST] <durandal_1707> it is not rejected [22:21:14 CEST] <durandal_1707> and you can create files with sox [22:31:39 CEST] <cone-868> ffmpeg 03Carl Eugen Hoyos 07master:d1b4ea2f6175: lavfi/showspatial: Remove two write-only variables. [22:31:54 CEST] <cehoyos> durandal_1707: Removed, thank you [22:46:26 CEST] <cone-868> ffmpeg 03Michael Niedermayer 07master:710b7ec07133: tools: Add fuzzer for demuxers [22:46:27 CEST] <cone-868> ffmpeg 03Michael Niedermayer 07master:5a6fc87443e2: avcodec/gdv: Check remaining output after decode 5/6/8/ [00:00:00 CEST] --- Sat Jun 1 2019

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ffmpeg.log.20190531
by burek 01 Jun '19

01 Jun '19

[02:28:53 CEST] <keegans> i've got some strange heap corruption going on in my ffmpeg C app , https://gist.github.com/meme/f42ad864229e917553331c50950b824b#file-ffmpeg_u… initially kicked off by avcodec_send_packet (see top of file for valgrind dump ) [02:29:10 CEST] <keegans> if someone could quickly take a look and see what exactly i'm missing , that'd be great . thanks [02:29:28 CEST] <keegans> i thought i was following the "avcodec_send_packet" contract properly ,though [02:38:14 CEST] <an3k> kepstin: I saw https://github.com/DolbyLaboratories/dolby-encoding-engine/blob/master/plug… and also some Dolby Vision mentions and thought they (accidentally) released an DV encoder :) [02:38:44 CEST] <keegans> av_read_frame itself is crashing with hls [04:40:23 CEST] <Mista_D> Does sr filter need a DNN file before it can be used? [11:52:04 CEST] <kingmoses> Its a must for one to use libavcodec58? My server has libavcodec57 and nothing runs. [11:52:52 CEST] <furq> that's a distro packaging question [11:53:14 CEST] <furq> if you have mismatched versions then it sounds like something's gone wrong with your package management [11:55:43 CEST] <kingmoses> furq, my dev machine is on debian buster and things work fine. My server runs on debian strech and i am getting some few problems there. [11:57:29 CEST] <kingmoses> But i am using this Golang binding https://github.com/giorgisio/goav [11:58:14 CEST] <kingmoses> and it requires libavcodec-dev which i presume is the latest version... [12:14:07 CEST] <justinasvd> Morning, guys. [12:14:55 CEST] <justinasvd> I have a question regarding avfft.h interface. How do you typically implement 2d Fourrier transforms using those functions? [12:16:03 CEST] <justinasvd> If I understand correctly, the provisioned functions only support 1d case, and then you simply do FFT line-by-line for a frame, no? [12:32:40 CEST] <kingmoses> I've encountered this error when running the code: error while loading shared libraries: libavcodec.so.58: cannot open shared object file: No such file or directory [12:40:45 CEST] <justinasvd> Either not installed or not in the library path. [12:40:47 CEST] <BtbN> If you try to run something on an ancient Debian version which does not have that library, that's not overly surprising. [12:41:08 CEST] <justinasvd> If you put your library into some exotic location, you can always specify LD_LIBRARY_PATH [12:41:09 CEST] <BtbN> Build it right there on that server, and hope it still supports the old version it has. [12:41:28 CEST] <BtbN> (And also considder updating that oldstable box) [12:51:42 CEST] <aruns> Hi, any tips on how to reduce the overall file size of an MP4 video with FFMPEG? [12:53:44 CEST] <BtbN> By reducing the quality [12:54:59 CEST] <aruns> I found https://linuxconfig.org/how-to-reduce-the-file-size-of-mpeg-4-multimedia-fo…, but now my video is not playable. [12:55:28 CEST] <BtbN> mpeg4 has not much to do with mp4 [12:55:35 CEST] <BtbN> Also, that "tutorial" is horrible [12:55:50 CEST] <furq> i didn't know ffmpeg was around 2018 years ago [12:56:32 CEST] <BtbN> Use crf if you want to reduce the quality. That commandline there would encode very high bitrate audio [13:00:30 CEST] <furq> it won't, it just assumes you mean -b:v [13:00:35 CEST] <furq> the post is still bad though [13:02:13 CEST] <furq> aruns: -i foo.mp4 -c:v libx264 -crf X -preset Y -c:a copy -movflags faststart bar.mp4 [13:02:16 CEST] <furq> change X and Y as desired [13:03:00 CEST] <furq> you won't be able to get significant gains without noticeably losing quality unless the source is massively oversized [14:21:50 CEST] <an3k> hmm, where can I find the SEI UUIDs for the various information, especially mastering display color? [14:22:45 CEST] <Gunstick> hi. I have a file with 5 mono channels. 1st 2 are muted. I want to line-graph the 3 others separately and mix them to a single audio stream. Current command line is: ffmpeg -t 20 -i You_Bore.wav -filter_complex "[0:a]showwaves=s=1280x720:split_channels=y:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a -c:v libx264 You_Bore.mkv [14:52:00 CEST] <fsphil> is there a handy (lazy) way I can provide a "-vf" style option in my program? [14:55:00 CEST] <DHE> custom libavfilter? a -vf style parameter can be handled by a single function which effectively only substitutes the supplied string into a single place. [00:00:00 CEST] --- Sat Jun 1 2019

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