historic m68k meeting video

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historic m68k meeting video

Christian T. Steigies
Hi,
some of you may remember that we had an m68k meeting in Kiel 10 years (and
one month) ago. I recorded the public talks of Wouter (debian secrets) and
Joey (debian administration) and some of the m68k discussions and I stumbled
upon the tapes this week. So I finally captured the video, it helps to have
larger disks than 10 years ago. The video is obviously not HD, the audio
volume is pretty low (especially of the m68k part), definetely not up to
debconf video standards. I wonder if anybody of the participants of that
meeting is interested in that video. I would have to convert this DV to mpeg
to cut down the size to something reasonable (any suggestions for ffmpeg
options?) before I could put it somewhere for download.

Christian

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Re: historic m68k meeting video

Wouter Verhelst
Hi Christian,

(note: Cc to debconf-video@ added)

On Sun, Sep 23, 2018 at 06:01:54PM +0200, Christian T. Steigies wrote:
> Hi,
> some of you may remember that we had an m68k meeting in Kiel 10 years (and
> one month) ago. I recorded the public talks of Wouter (debian secrets) and
> Joey (debian administration) and some of the m68k discussions and I stumbled
> upon the tapes this week. So I finally captured the video, it helps to have
> larger disks than 10 years ago.

Heh, right :-)

> The video is obviously not HD, the audio volume is pretty low
> (especially of the m68k part), definetely not up to debconf video
> standards.

We can fix audio levels easily.

> I wonder if anybody of the participants of that meeting is interested
> in that video.

I think it makes sense to have them. Obviously much of it will be
outdated by now, but sometimes it can still be useful to refer to "this
is how we did things before". And it definitely was a Debian-related
event, so...

Note though: there already is an encoded version of the "mk68k future"
meeting that we had at the time in the DebConf video archive, under
<https://meetings-archive.debian.net/pub/debian-meetings/2008/m68k-meeting-kiel/>.
The other two events are not there, however.

> I would have to convert this DV to mpeg to cut down the
> size to something reasonable (any suggestions for ffmpeg options?)

Probably best to use VP9 rather than MPEG then.

Try this:

First, cut the video into different files, one for each target output
file you'd like to create. You can do that with, say, kdenlive, or you
can use ffmpeg for that too:

ffmpeg -ss <start time> -t <video length> -i foo.dv -c:v copy -c:a copy
output.dv

where <start time> is the time from the start of the file, in
(optionally fractional) seconds, where the content starts, and
<video length> is the length of the event, again in (fractional)
seconds, of the target video.

Then, run the following three steps on each file:

- First pass video encode:

ffmpeg -i foo.dv -c:v libvpx-vp9 -c:a libopus -b:v 750 -minrate 375
-maxrate 1088 -crf 33 -tile-columns 1 -threads 4 -quality good -pass 1
-speed 4 -y <output>.webm

- Audio normalize:

ffmpeg -i foo.dv -c:a copy -y foo.wav
bs1770gain -a -o $(pwd) foo.wav
# the second command creates a "foo.flac" with normalized audio levels,
# so they're easier to hear

- Second pass video encode:

ffmpeg -i foo.dv -i foo.flac -c:v libvpx-vp9 -c:a libopus -b:v 750
-minrate 375 -maxrate 1088 -crf 33 -tile-columns 1 -threads 4 -quality
good -pass 2 -speed 4 -map 0:v -map 1:a <output>.webm

If you care more about not using too many cores than about encoding
speed, drop the "-tile-columns 1 -threads 4" bit of each ffmpeg command
line to have a single-threaded encode instead of running at 4 threads.

Note, the numbers are optimized for SD video. If you're trying to encode
HD video, you'll need to update them. Google has some pretty good
documentation on how to do that at
https://developers.google.com/media/vp9/

> before I could put it somewhere for download.

Once you've done the above, I'd be happy to put them up at
video.debian.net...

Alternatively, if you have the bandwidth, we can simply upload the .dv
file to vittoria.debian.org (the encoder machine for Debconf video), and
then I can throw everything through SReview which can do all of the
above (and more!) for you.

--
Could you people please use IRC like normal people?!?

  -- Amaya Rodrigo Sastre, trying to quiet down the buzz in the DebConf 2008
     Hacklab

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Re: historic m68k meeting video

Bob-2
You guys are awesome. Thank you for this, Wouter!


On Tue, Sep 25, 2018 at 10:31 AM, Wouter Verhelst
Hi Christian,

(note: Cc to debconf-video@ added)

On Sun, Sep 23, 2018 at 06:01:54PM +0200, Christian T. Steigies wrote:
> Hi,
> some of you may remember that we had an m68k meeting in Kiel 10 years (and
> one month) ago. I recorded the public talks of Wouter (debian secrets) and
> Joey (debian administration) and some of the m68k discussions and I stumbled
> upon the tapes this week. So I finally captured the video, it helps to have
> larger disks than 10 years ago.

Heh, right :-)

> The video is obviously not HD, the audio volume is pretty low
> (especially of the m68k part), definetely not up to debconf video
> standards.

We can fix audio levels easily.

> I wonder if anybody of the participants of that meeting is interested
> in that video.

I think it makes sense to have them. Obviously much of it will be
outdated by now, but sometimes it can still be useful to refer to "this
is how we did things before". And it definitely was a Debian-related
event, so...

Note though: there already is an encoded version of the "mk68k future"
meeting that we had at the time in the DebConf video archive, under
<https://meetings-archive.debian.net/pub/debian-meetings/2008/m68k-meeting-kiel/>.
The other two events are not there, however.

> I would have to convert this DV to mpeg to cut down the
> size to something reasonable (any suggestions for ffmpeg options?)

Probably best to use VP9 rather than MPEG then.

Try this:

First, cut the video into different files, one for each target output
file you'd like to create. You can do that with, say, kdenlive, or you
can use ffmpeg for that too:

ffmpeg -ss <start time> -t <video length> -i foo.dv -c:v copy -c:a copy
output.dv

where <start time> is the time from the start of the file, in
(optionally fractional) seconds, where the content starts, and
<video length> is the length of the event, again in (fractional)
seconds, of the target video.

Then, run the following three steps on each file:

- First pass video encode:

ffmpeg -i foo.dv -c:v libvpx-vp9 -c:a libopus -b:v 750 -minrate 375
-maxrate 1088 -crf 33 -tile-columns 1 -threads 4 -quality good -pass 1
-speed 4 -y <output>.webm

- Audio normalize:

ffmpeg -i foo.dv -c:a copy -y foo.wav
bs1770gain -a -o $(pwd) foo.wav
# the second command creates a "foo.flac" with normalized audio levels,
# so they're easier to hear

- Second pass video encode:

ffmpeg -i foo.dv -i foo.flac -c:v libvpx-vp9 -c:a libopus -b:v 750
-minrate 375 -maxrate 1088 -crf 33 -tile-columns 1 -threads 4 -quality
good -pass 2 -speed 4 -map 0:v -map 1:a <output>.webm

If you care more about not using too many cores than about encoding
speed, drop the "-tile-columns 1 -threads 4" bit of each ffmpeg command
line to have a single-threaded encode instead of running at 4 threads.

Note, the numbers are optimized for SD video. If you're trying to encode
HD video, you'll need to update them. Google has some pretty good
documentation on how to do that at
https://developers.google.com/media/vp9/


> before I could put it somewhere for download.


Once you've done the above, I'd be happy to put them up at
video.debian.net...

Alternatively, if you have the bandwidth, we can simply upload the .dv
file to vittoria.debian.org (the encoder machine for Debconf video), and
then I can throw everything through SReview which can do all of the
above (and more!) for you.

--
Could you people please use IRC like normal people?!?

  -- Amaya Rodrigo Sastre, trying to quiet down the buzz in the DebConf 2008
    Hacklab



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Re: historic m68k meeting video

Christian T. Steigies
In reply to this post by Wouter Verhelst
Sorry for the delay...

On Tue, Sep 25, 2018 at 04:31:27PM +0200, Wouter Verhelst wrote:
>
> We can fix audio levels easily.

I seem to have problems with this part.
 
> - Audio normalize:
>
> ffmpeg -i foo.dv -c:a copy -y foo.wav

This produces a lot of this:
Error decoding audio, skipping audio package: frame_reader_run(), "ffsox_frame_reader.c" (151).

And the resulting audio file is garbage (has the correct length, though).
When I play the input file with vlc, the audio is ok.

Christian

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Re: historic m68k meeting video

Wouter Verhelst-5
Hi Christian,

On Sun, Oct 14, 2018 at 11:30:27AM +0200, Christian T. Steigies wrote:
> Sorry for the delay...

No worries, it happens.

> On Tue, Sep 25, 2018 at 04:31:27PM +0200, Wouter Verhelst wrote:
> >
> > We can fix audio levels easily.
>
> I seem to have problems with this part.

Hrm.

> > - Audio normalize:
> >
> > ffmpeg -i foo.dv -c:a copy -y foo.wav
>
> This produces a lot of this:
> Error decoding audio, skipping audio package: frame_reader_run(), "ffsox_frame_reader.c" (151).
>
> And the resulting audio file is garbage (has the correct length, though).
> When I play the input file with vlc, the audio is ok.

I guess that means that the audio codec used for the dv file can't be
used in a .wav container. I thought DV always used LPCM, but perhaps
that's my mistake.

You can just drop the -c:a copy; that will convert it to linear PCM
(probably at smaller bitdepth, but that's fine, will have to be
downsampled anyway).

If that also fails, maybe run this:

ffmpeg -i <source> -t 60 -c copy fragment.dv

which creates a one-minute sample in "fragment.dv", and then put that
oneline somewhere, so I can see what's happening.

--
To the thief who stole my anti-depressants: I hope you're happy

  -- seen somewhere on the Internet on a photo of a billboard

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Re: historic m68k meeting video

Christian T. Steigies
On Sun, Oct 14, 2018 at 12:49:32PM +0200, Wouter Verhelst wrote:
>
> I guess that means that the audio codec used for the dv file can't be
> used in a .wav container. I thought DV always used LPCM, but perhaps
> that's my mistake.

Ah, my bad. The capture from kino seems to be in a different format (mkv),
with the dv capture everything seems to work. Now which button do I press to
reduce the audio noise? But the volume is much better already.

Christian

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Re: historic m68k meeting video

Wouter Verhelst
Hi,

On Sun, Oct 14, 2018 at 05:14:07PM +0200, Christian T. Steigies wrote:
> On Sun, Oct 14, 2018 at 12:49:32PM +0200, Wouter Verhelst wrote:
> >
> > I guess that means that the audio codec used for the dv file can't be
> > used in a .wav container. I thought DV always used LPCM, but perhaps
> > that's my mistake.
>
> Ah, my bad. The capture from kino seems to be in a different format (mkv),
> with the dv capture everything seems to work.

Cool.

> Now which button do I press to reduce the audio noise? But the volume is much
> better already.

I'm afraid that's much more difficult to fix automatically. Obviously if
you turn up the volume, the background noise gets turned up, too. It is
possible to fix this with some audio filters if you know what you're
doing, but I'm not an expert in the matter. Maybe someone on the list
here does know how to do that?

I'll give it a few days; if nobody speaks up, I'll publish the talks on
video.debian.net as-is.

--
To the thief who stole my anti-depressants: I hope you're happy

  -- seen somewhere on the Internet on a photo of a billboard