[Ffmpeg-devel-irc] ffmpeg.log.20181207

[burek]

[01:43:16 CET] <Soni> how do I use ffmpeg to mix multiple audio files together?
[01:43:22 CET] <Soni> at different positions
[01:43:27 CET] <Soni> y'know, like an audacity project
[01:43:34 CET] <Soni> can ffmpeg do that?
[01:44:00 CET] <Soni> can ffmpeg read stuff from a file?
[01:44:20 CET] <Soni> (commands etc)
[04:33:38 CET] <raytiley> is there a way to take something like `-vf scale=w=640:h=360:force_original_aspect_ratio=decrease` and make it round to even pixels?
[04:47:23 CET] <furq> raytiley: scale=640:-2 or scale=-2:360
[04:47:48 CET] <furq> or if you need to handle any AR, scale="if(gt(a\,16/9)\,640\,-2):if(gt(a\,16/9)\,-2\,360)"
[04:48:42 CET] <raytiley> furq: thanks, just stumbled on that
[11:20:23 CET] <dv_> hmm what parts of a video codec benefit most from hw acceleration on embedded devices?
[11:20:34 CET] <Mavrik> All of them? :)
[11:20:43 CET] <Mavrik> It's usually a full decoding / encoding block on the SoC
[11:20:51 CET] <dv_> I mean, assume that you have a hw codec whose driver is fully open source, so you can access all of the hardware's facilities.
[11:21:10 CET] <Mavrik> You're assuming that the pipeline is programmable.
[11:21:11 CET] <dv_> isnt the hardware usually made up of units that do individual steps, like DCT, motion compensation, deblocking etc.?
[11:21:18 CET] <Mavrik> But it's usually a hardwired block that does a full decode
[11:21:20 CET] <Mavrik> And a full encode
[11:21:47 CET] <Mavrik> Which is configurable to some extent but not really programmable
[11:22:05 CET] <JEEB> at some point intel noted that they might open up APIs for specific parts of H.264, but then that person was mysteriously vanished, never to be seen again
[11:28:07 CET] <dv_> hmm
[11:28:15 CET] <dv_> Mavrik: ever seen anything about Hantro hw codecs?
[13:52:20 CET] <alonex> .
[13:52:56 CET] <alonex> Hello, any one know right syntax of QSV h264 encoding?
[14:18:43 CET] <alonex> i want to use ffmpeg for screen capturing with QSV instead h264 lossless, but i can't. With bandicam qsv working.
[14:20:30 CET] <JEEB> pretty sure QSV doesn't support lossless H.264?
[14:22:10 CET] <alonex> hello jeeb, i guess qsv does not supporting lossless with h264, but with bandicam i use 100% of quolity with 5 frames per second rate
[14:22:24 CET] <alonex> and h264 with QSV - it's ok.
[14:22:33 CET] <alonex> CPU almost iddle
[14:22:44 CET] <alonex> but i want my lovely ffmpeg for that
[14:57:28 CET] <alonex> .
[14:57:39 CET] <alonex> Jeeb u here?
[14:57:56 CET] <alonex> hello jeeb, i guess qsv does not supporting lossless with h264, but with bandicam i use 100% of quolity with 5 frames per second rate
[14:58:02 CET] <alonex> and h264 with QSV - it's ok.
[14:58:05 CET] <alonex> but i want my lovely ffmpeg for that
[18:15:10 CET] <brimestone> Hello everyone.. I'm getting an issue when transcoding an XDCAM proxy into mp4 where the resulting mp4 has a few seconds of repeated last frame.
[21:14:19 CET] <petecouture> Has anyone run into an issue of coverting a webcam -> wowza recorded flv1 video to mp4 using FFMPEG. And during the process theres a timing issue where 3 minutes are stretched out into 40 minutes? Like suddenly the video and audio slow down to 1/16 speed.
[21:14:37 CET] <petecouture> Its a 5 minute recording and the first minute and last minute play fine.
[21:18:55 CET] <djk> I had an ffmpeg setup to stream to facebook at 720 unfortunately lost the that working configuration. The stream I have setup now Facebook only show 480 as the highest option. any suggestions? https://pastebin.com/dQfRbSVC
[21:19:21 CET] <JEEB> note: you don't need 44.1kHz unless Facebook requires that
[21:19:44 CET] <JEEB> post the full log for that?
[21:19:47 CET] <JEEB> on a pastebin
[21:19:49 CET] <JEEB> and link
[21:19:59 CET] <JEEB> because that looks as if you're setting 1280x720 and then not scaling
[21:20:05 CET] <JEEB> so if something's doing something, it's facebook :P
[21:20:36 CET] <djk> JEEB: so it looks right to you?
[21:21:25 CET] <djk> and the 44.1 I recall is Facebook requirement have to double check. It is silent anyway
[21:21:33 CET] <JEEB> can't say anything from just the command, but if you look at the log and it clearly encodes 720p then you can only ask facebook
[21:21:46 CET] <JEEB> yea facebook might be requiring it due to a stupid wording in the FLV spec :P
[21:21:49 CET] <JEEB> the spec literally says
[21:21:57 CET] <djk> https://www.facebook.com/BRPCwebcam
[21:22:06 CET] <JEEB> "for AAC we want 44.1kHz as the value written in the FLV header"
[21:22:12 CET] <JEEB> and then the next sentence
[21:22:22 CET] <JEEB> "we will promptly ignore this value in players and trust the AAC stream instead"
[21:22:29 CET] <djk> that is the live stream.
[21:22:37 CET] <JEEB> cue over 9000 vendors which limited AAC to 44.1kHz :P
[21:22:40 CET] <JEEB> (and stereo)
[21:22:55 CET] <atomnuker> JEEB: so the aac samplerate?
[21:22:55 CET] <JEEB> even though the spec says "we promptly ignore these two values and trust the AAC stream"
[21:23:06 CET] <JEEB> atomnuker: yes, AAC configuration
[21:23:11 CET] <atomnuker> lul
[21:23:12 CET] <JEEB> as yoü'd expect
[21:23:31 CET] <JEEB> only the FLV header contains the pre-defined values (stereo, 44.1kHz)
[21:23:52 CET] <JEEB> but yea, that's why all those video services with FLV ended up with 44.1kHz AAC
[21:23:59 CET] <JEEB> because they skipped the second sentence
[21:24:12 CET] <djk> :-/
[21:26:11 CET] <djk> JEEB: what else do you need or does what I have setup look right?
[21:26:58 CET] <JEEB> I have no idea what *facebook* needs
[21:27:00 CET] <djk> JEEB: and it is just Facebook messing with the stream making 480 the best view
[21:27:11 CET] <JEEB> if you see in your log that the encoded resolution is 720p
[21:27:11 CET] <petecouture> Ive figured out the answer to my question. If anyone else runs into this legacy issue with Flash -> Wowza. The video was recorded with a variable framerate which players handle differently from flv to mp4 when you re-encode it. Most players keep th einitial framerate and then adjust the playback speed to match any variences. The key to fixing it is to define a flat rate or -r 30 when youre reencoding from flv to mp4
[21:27:27 CET] <JEEB> atomnuker: https://wwwimages2.adobe.com/content/dam/acom/en/devnet/flv/video_file_format_spec_v10_1.pdf
[21:27:30 CET] <JEEB> page 71
[21:27:37 CET] <JEEB> fourth paragraph
[21:28:15 CET] <djk> JEEB: https://www.facebook.com/help/publisher/162540111070395?helpref=page_content
[21:28:16 CET] <JEEB> petecouture: if the timestamps make sense it should be remuxable
[21:41:03 CET] <djk> JEEB: I updated the with the nohup.out log https://pastebin.com/dQfRbSVC
[22:43:53 CET] <alonex> i want to use ffmpeg for screen capturing with QSV instead h264 lossless, but i can't. With bandicam qsv working.
[22:44:06 CET] <alonex> Hello, any one know right syntax of QSV h264 encoding?
[00:00:00 CET] --- Sat Dec  8 2018