[Ffmpeg-devel-irc] ffmpeg.log.20180527

[burek]

[00:05:10 CEST] <JEEB> well if you're asking for interleaved stuff then the result goes into a single buffer? and what's your requested sample format?
[00:07:32 CEST] <shfil> AV_SAMPLE_FMT_S16
[00:09:14 CEST] <shfil> I do this: https://gist.github.com/ShFil119/ebd0cf30632c89aa393913b1abf52594#file-resampling-L221
[00:09:21 CEST] <shfil> (updated)
[00:09:34 CEST] <JEEB> signed, 16bit samples then, each channel after each other in a single buffer
[00:09:52 CEST] <JEEB> if you needed multiple buffers then the P one is the one you want
[00:11:03 CEST] <shfil> openAL wants one buffer with interleaved data irrc
[00:58:24 CEST] <johnnny22> humm sidx_pts vs tfdt_dts :o
[00:58:35 CEST] <johnnny22> having the time of my life :P
[00:58:58 CEST] <JEEB> :D
[01:00:20 CEST] <JEEB> also if you're dealing with MOV/MP4 make sure https://patchwork.ffmpeg.org/patch/8980/ doesn't help you if applied
[01:00:35 CEST] <JEEB> I haven't had time to try and review it and nobody else seems to be capable of reviewing the mess that google/youtube left
[01:02:31 CEST] <johnnny22> I'll def give it a try
[01:02:56 CEST] <johnnny22> just those 2 lines ?
[01:05:34 CEST] <JEEB> yes
[01:09:48 CEST] <johnnny22> The issue I'm dealing with is more like: Audio source has an sidx_pts, so the tfdt_dts isn't used. And the video source has no sidx_pts, so the found tfdts_dts is used  (within mov.c mov_read_trun). Swapped the if/else just to "try", to get both to use the tfdt value to set the 'dts' value. But the main problem in my case, is that the video source has a tfdt_dts that is zerobase timestamps,
[01:09:48 CEST] <johnnny22> while the audio source sidx_pts uses system-time timestamps. Basically, something seems screwed in the source.
[01:11:21 CEST] <johnnny22> But maybe i should approach it differently  :P
[01:12:03 CEST] <johnnny22> Obviously, fixing at the encoder level is probably better, but ... for now I'm just trying to grasp the issue.
[01:12:30 CEST] <johnnny22> I'll still try the patch though.
[01:21:06 CEST] <johnnny22> But i think my src is on 3.4.1 :P  lol
[01:22:05 CEST] <johnnny22> the issue i was testing though showed up on both 3.4.1 and 4.0 and nightly build (i'm sure it's the video source the issue)
[01:23:45 CEST] <johnnny22> i'll update to <master> and see
[01:28:04 CEST] <johnnny22> or should i try <release/4.0> instead ?
[01:30:32 CEST] <johnnny22> patch lines make more sense now :P  older version didn't have those :)
[01:52:34 CEST] <johnnny22> humm, fun, it's complaining that ffserver ain't found..
[01:52:46 CEST] <johnnny22> *my rpm builder
[01:53:26 CEST] <nicolas17> johnnny22: https://ffmpeg.org/index.html#ffserv there is no ffserver anymore
[01:53:36 CEST] <johnnny22> good to know :D
[01:53:51 CEST] <johnnny22> at least i'm not depending on it ;)
[01:58:03 CEST] <johnnny22> This .spec file i got is strange  ;)
[04:35:59 CEST] <nicolas17> with the API, can I seek to and decode a specific frame, by frame number?
[04:36:17 CEST] <nicolas17> it seems like the ffmpeg CLI asks for a timestamp, I can't use frame numbers
[04:36:36 CEST] <nicolas17> I'd have to convert to a timestamp based on fps and that could have rounding errors and blah
[04:38:24 CEST] <furq> nicolas17: https://ffmpeg.org/doxygen/trunk/group__lavf__decoding.html#gaa23f7619d8d4ea0857065d9979c75ac8
[04:38:50 CEST] <furq> "timestamp" there is pts, which is frame number * timebase
[04:40:03 CEST] <furq> also a lot of filters let you specify a frame number or pts, so if you just want to trim or something then that's an option
[04:42:19 CEST] <nicolas17> hm that says "to the keyframe", would I need to write my own stuff to decode from there to the actual frame I want?
[05:45:44 CEST] <fa0> Hello
[05:46:09 CEST] <fa0> I'm muxing avi to mp4 and when doing so I'm getting this message;
[05:46:32 CEST] <fa0> Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly pts has no value
[05:46:50 CEST] <fa0> I've been looking around, seeing some options discussed, but not sure, what to use?
[12:17:56 CEST] <d-safinaskar> i have grayscale video. every pixel ocupies 8 bits. is there some filter which reduces number of bits used to store pixel and then expand number of bits back to 8?
[12:18:17 CEST] <d-safinaskar> i. e. i want some filter which simple zeroes out some least significant bits
[12:18:42 CEST] <d-safinaskar> this will make video quality lower and makes it more situable to lossless compressing
[12:18:48 CEST] <d-safinaskar> i will try to describe my use case
[12:18:55 CEST] <d-safinaskar> i always capture video from screen
[12:19:19 CEST] <d-safinaskar> i want to compress it to make it occupy minimal space
[12:19:55 CEST] <d-safinaskar> unfortunately screen video has some its own specifics, so usual lossy compression methods which are used for movies are unsituable
[12:20:22 CEST] <d-safinaskar> so i decided to reduce color space and then apply some lossless compression
[12:20:37 CEST] <d-safinaskar> i already convert my video to grayscale to reduce information
[12:21:03 CEST] <d-safinaskar> then i want to reduce number of bits in pixel. i think 4 bits will be enought, i don't need all 8 bits
[12:21:21 CEST] <d-safinaskar> and then i will apply some lossy compression, for example, ffv1
[12:21:44 CEST] <d-safinaskar> so, how to throw away some low-significant bits from every grayscale pixel?!
[12:31:41 CEST] <durandal_1707> d-safinaskar: lut filter....
[12:44:06 CEST] <d-safinaskar> durandal_1707: thanks a lot
[12:44:13 CEST] <d-safinaskar> durandal_1707: i am trying lutyuv=y='bitand(val,128+64+32)':u=128:v=128
[12:44:18 CEST] <d-safinaskar> durandal_1707: but i get error
[12:44:27 CEST] <d-safinaskar> durandal_1707: No such filter: '128+64+32):u'
[12:44:33 CEST] <d-safinaskar> durandal_1707: please help
[12:44:39 CEST] <durandal_1707> d-safinaskar: escape ,
[12:44:41 CEST] <d-safinaskar> durandal_1707: probably some problem with quotation
[12:44:51 CEST] <durandal_1707> with \
[12:45:13 CEST] <d-safinaskar> durandal_1707: thanks
[12:56:05 CEST] <probook> hello
[12:58:10 CEST] <probook> ffmpeg-compact-57 PGP problem with arch linux instalation
[13:28:23 CEST] <d-safinaskar> what is usual fps? 24 fps or 25 fps?
[13:28:32 CEST] <d-safinaskar> different sources give different answers?
[13:28:49 CEST] <d-safinaskar> what is usual fps for movies, say, dvd movies? 24 fps or 25 fps?
[13:28:51 CEST] <d-safinaskar> for TV?
[13:33:30 CEST] <BtbN> Whatever the creator decided to use
[13:33:52 CEST] <BtbN> and also depends on what continend he lived on
[13:36:24 CEST] <JEEB> generally you just want to output the same timestamps as input
[13:58:25 CEST] <ariyasu> tv framerate depends on region d-safinaskar
[13:59:14 CEST] <JEEB> that's why you generally keep the input timestamps, only exception is when you have to do something like IVTC
[13:59:18 CEST] <ariyasu> pal regions broadcast at 25fps or 50fps, ntsc regions broadcast at 23.976fps 29.970, usually
[13:59:23 CEST] <JEEB> but in that case you've looked at the content
[14:08:30 CEST] <d-safinaskar> what fps is used in DVD and bluray?
[14:09:27 CEST] <JEEB> blu-ray lets you do different rates at different resolutions etc
[14:10:14 CEST] <JEEB> but why would you care since in general you don't want to change it?
[14:14:21 CEST] <d-safinaskar> JEEB: i want to capture my screen. i want to set framerate to 24 or 25. also i am perfectionist, so i am curious what of this two numbers is *THE RIGHT WAY* - 24 or 25
[14:15:10 CEST] <JEEB> uhh
[14:15:18 CEST] <JEEB> what's the use case and all that shiz
[14:15:49 CEST] <JEEB> basically if it's games and such you just capture at 60/1.001 and if you're ever going to make a commercial blu-ray out of it just downscale to 720p and you can utilize 60/1.001 mode
[14:16:31 CEST] <JEEB> (or capture at plain 60 depending on your screen's refresh rate, you can always then do the /1.001 thing later with a minimal change to the audio as far as I can see)
[14:17:06 CEST] <JEEB> but really, there is no "right" frame rate, other than the frame rate for your use case that you can handle the best with your setup
[14:33:55 CEST] <kerio> modern games are 60 sharp, right
[14:34:02 CEST] <kerio> we left ntsc behind
[14:37:16 CEST] <JEEB> it all depends on the screen refresh rate
[14:37:34 CEST] <JEEB> a lot of screen refresh rates are still 60/1.001, games in general can output whatever they want but vsync is generally set to your screen
[14:41:42 CEST] <ariyasu> console gaming is a crap shoot
[14:41:52 CEST] <ariyasu> they may be aiming for 60 or 30
[14:41:59 CEST] <ariyasu> but often drop frames
[14:42:13 CEST] <ariyasu> it's rare a game is ever locked without dropping frames
[14:42:23 CEST] <ariyasu> unless it's retro stuff
[14:42:24 CEST] <JEEB> that's a separate thing of course
[14:42:51 CEST] <JEEB> you would still be capturing those at the refresh rate
[14:43:01 CEST] <JEEB> and then if you really wanted to do VFR later you could do that
[14:43:28 CEST] <JEEB> or if the refresh is at 30(/1.001) then you could just select the duplicates and remove them
[14:43:41 CEST] <JEEB> s/refresh/actual frame rate/
[14:45:48 CEST] <kerio> ariyasu: old games have lag frames all over the place yo
[14:52:33 CEST] <kerio> JEEB: there's no "right" frame rate but we can all agree that 59.94 is wrong
[14:53:11 CEST] <JEEB> well if your screen refresh rate is that, your thing is going to vsync and render at that rate max
[14:53:26 CEST] <JEEB> but yes, it shouldn't exist in many modern use cases
[14:54:05 CEST] <JEEB> if you then need to make a commercial blu-ray with /1.001 you can then always poke at the audio a wee bit and call it a day
[15:36:53 CEST] <shfil> JEEB do you know what can cause quiet "ticking" in sound resampled from mono to stereo?
[15:37:55 CEST] <JEEB> nope
[15:40:29 CEST] <shfil> maybe even more "scraping" than "ticking".
[15:47:37 CEST] <d-safinaskar> is there some lossless (this may be compressed or uncompressed format such as yuv4mpeg2) format which can store grayscale video, where every pixel ocupies 2 bits?
[15:49:07 CEST] <shfil> JEEB: with files don't recognized by ffmpeg(codec doesn't see it's mono) it happens.
[21:33:16 CEST] <johnnny22> JEEB: that patch didn't solve my issue ;)
[21:33:39 CEST] <johnnny22> Who knows, maybe it solved another problem that I haven't seen yet though.
[21:35:36 CEST] <JEEB> yes, it does. and I didn't think it'd solve your issue most likely
[21:36:39 CEST] <johnnny22> I wish I had another fMP4 hls sample to test with.. one done by ffmpeg. One that uses systemtime timestamps
[21:40:29 CEST] <johnnny22> think i might have found at least the base command, just not sure about the timestamps yet.
[21:58:16 CEST] <johnnny22> omg, hls_flags are nice, never noticed them in older versions ( append_list )
[23:02:04 CEST] <shfil> as I have a lot problems with swresampler(artifacts with mono pcm wav), is there possibility to force usage of decoder mp3(notFloat)?
[23:02:30 CEST] <shfil> (in ffmpeg 4.0)
[23:10:38 CEST] <JEEB> shfil: can you make a simple test case that makes it happen and file that on trac.ffmpeg.org ?
[23:10:50 CEST] <JEEB> also yes, you should be able as the default was all that got changed
[23:16:35 CEST] <shfil> you mean create bug report?
[23:17:38 CEST] <JEEB> yes. in the worst case you get told what you did wrong, but if there's anything wrong with swresample then that might be figured out as well
[23:46:19 CEST] <slavanap> Hi! Is there any simple algorithms for 2 audio files synchronization, if one of them has noise?
[23:46:46 CEST] <durandal_1707> simple? no
[23:47:56 CEST] <fa0> Hello all
[23:48:36 CEST] <fa0> I'm muxing/copying some videos, making some changes, and I noticed on one video this metadata lines 9-16; http://dpaste.com/2Z3V9XC
[23:49:31 CEST] <durandal_1707> and?
[23:49:32 CEST] <slavanap> durandal_1707, okay. Any complex ones? I have mathematical education, I can handle it, but it'll be longer.
[23:49:43 CEST] <fa0> The only thing I've come up with so far is to use, '-map_metadata 0:g' but then this is what I end up with, the 'handler_name' changes;  http://dpaste.com/1H7P9DD
[23:50:06 CEST] <fa0> SO, how can I get all the metadata to copy exaclty?
[23:51:37 CEST] <slavanap> Like, how Adobe Audition sync the speech? https://digicompdiy.wordpress.com/2012/10/15/automatically-sync-up-two-audio-files/     I wonder what's the underlying mathematical model used for that purpose, except full search for lower SND value.
[23:51:52 CEST] <JEEB> shfil: thanks
[23:51:55 CEST] <slavanap> *lower->the lowest
[23:53:10 CEST] <shfil> JEEB nope I should be thanking ;) thanks for earlier help
[23:53:38 CEST] <JEEB> I hope cehoyos et al will parse that the issue is actually with swresample
[23:54:00 CEST] <fa0> Hmm I tried like this, but not working; -metadata:s:s:0 handler="GPAC ISO Audio Handler"
[23:54:00 CEST] <johnnny22> JEEB: do you think that patch has to do with the "[lavf] Edit lists are not correctly supported (FFmpeg issue)." error ?
[23:54:44 CEST] <JEEB> johnnny22: yes, we've had fun with the google/youtube edit list thing since inception
[23:54:54 CEST] <JEEB> since it tries to do presentation level stuff on the demuxer level
[23:55:06 CEST] <johnnny22> k, will try to build the player with the patch.
[23:55:29 CEST] <JEEB> although no idea about this thing you're noting other than "lol edit lists in FFmpeg"
[23:55:40 CEST] <JEEB> you can disable the google/youtube code and a lot of players seem to do that
[23:56:07 CEST] <fa0> In ffmpeg-3.4.2, I thought these options worked for supplying a name for the handler_name? -metadata:s:s:0 handler="Name"
[23:57:05 CEST] <johnnny22> how can i disable that google/youtube code thingny you talk about ? :)
[23:57:29 CEST] <durandal_1707> slavanap: tried python code (audiosync) that sync audio?, it doesnt look that complicated
[23:58:04 CEST] <JEEB> http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavformat/mov.c;h=f2a540ad507918a09536c60d61429d9fe3b517d2;hb=HEAD#l7705
[23:58:15 CEST] <JEEB> -advanced_editlist 0 I think
[23:58:22 CEST] <JEEB> before the input as it's an input option
[23:59:45 CEST] <durandal_1707> slavanap: you could use crosscorrelation that is very simple and very brute force and probably slow
[00:00:00 CEST] --- Mon May 28 2018