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Old 12-24-2011, 09:36 AM
Dale
 
Default Video editing advice on formats and size of file

Dale wrote:


I been doing some testing on this. I went to about the end of a 3
hour video. By the time it gets near the end of the video, the sound
is almost 1.4 seconds off. I tested this by telling smplayer to
adjust the audio delay. It is a bit annoying to see something on
screen then hear it a second or so later. It's like seeing a
explosion at a distance. You see it then have to wait for the sound
wave to hit you. When I am midways of the video, it is about .6 to .7
seconds off. So, it gets farther off as it goes. It's most likely
one step off that just gets worse as it goes.


I tried a couple other commands but I get errors about the file type.
I think a couple movies are in flv1 which is old. I may have to
convert them then stitch them together, which may not do the sound any
good then either. lol


Well, I got something to play with.

Dale

:-) :-)



Well, I tried to go to sleep and come back to this tomorrow. I couldn't
sleep so here I am again. While laying there I came up with a idea. I
stitched the first two videos together into a temporary file. Then I
stitched the temporary file to the 3rd video. The sound is off but it
sort of resets when it reached the stitch point so it is a good bit
closer than it was.


If I ever get me a video camera, I'm going to know to not break up
videos if I ever plan to put them back together again. It appears that
when you break the video, it is like humpty dumpty. You just can't
quite get it back together again.


At least this way is faster tho. Thanks to all for the ideas. I'm
still testing things.


Dale

:-) :-)

--
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!

Miss the compile output? Hint:
EMERGE_DEFAULT_OPTS="--quiet-build=n"
 
Old 12-24-2011, 02:41 PM
Michael Mol
 
Default Video editing advice on formats and size of file

On Sat, Dec 24, 2011 at 5:36 AM, Dale <rdalek1967@gmail.com> wrote:
> Dale wrote:
>>
>>
>> I been doing some testing on this. *I went to about the end of a 3 hour
>> video. *By the time it gets near the end of the video, the sound is almost
>> 1.4 seconds off. *I tested this by telling smplayer to adjust the audio
>> delay. *It is a bit annoying to see something on screen then hear it a
>> second or so later. *It's like seeing a explosion at a distance. *You see it
>> then have to wait for the sound wave to hit you. *When I am midways of the
>> video, it is about .6 to .7 seconds off. *So, it gets farther off as it
>> goes. *It's most likely one step off that just gets worse as it goes.
>>
>> I tried a couple other commands but I get errors about the file type. *I
>> think a couple movies are in flv1 which is old. *I may have to convert them
>> then stitch them together, which may not do the sound any good then either.
>> lol
>>
>> Well, I got something to play with.
>>
>> Dale
>>
>> :-) *:-)
>>
>
> Well, I tried to go to sleep and come back to this tomorrow. *I couldn't
> sleep so here I am again. *While laying there I came up with a idea. *I
> stitched the first two videos together into a temporary file. *Then I
> stitched the temporary file to the 3rd video. *The sound is off but it sort
> of resets when it reached the stitch point so it is a good bit closer than
> it was.
>
> If I ever get me a video camera, I'm going to know to not break up videos if
> I ever plan to put them back together again. *It appears that when you break
> the video, it is like humpty dumpty. *You just can't quite get it back
> together again.
>
> At least this way is faster tho. *Thanks to all for the ideas. *I'm still
> testing things.

There are ways to fix the sync, I just don't know what they are. Don't
give up hope.

Though...hm. One thing you might try is keeping the 'video' streams in
'copy' mode, but transcode the audio streams to something like 256kb/s
MP3. It'll increase your file size slightly, but the tools may be
clever enough to maintain sync better that way.


--
:wq
 
Old 12-24-2011, 04:42 PM
pk
 
Default Video editing advice on formats and size of file

On 2011-12-24 16:41, Michael Mol wrote:

> Though...hm. One thing you might try is keeping the 'video' streams in
> 'copy' mode, but transcode the audio streams to something like 256kb/s
> MP3. It'll increase your file size slightly, but the tools may be
> clever enough to maintain sync better that way.

If I remember correctly Avidemux has an option to calculate the original
video file audio length (if the audio is VBR). Not sure how this would
work with two files though; perhaps you would need to do this for each
file first and then adjust accordingly? I guess the only way to find out
is to play with it...

Merry xmas!

Peter K
 
Old 01-01-2012, 05:56 PM
Mick
 
Default Video editing advice on formats and size of file

On Saturday 24 Dec 2011 01:55:43 Dale wrote:
> Grant Edwards wrote:
> > On 2011-12-23, Dale<rdalek1967@gmail.com> wrote:
> >> Howdy,
> >>
> >> I been trying to get this to work right for a goooooood while now. I'm
> >> confused here. I have some videos that I download that are split up.
> >> Some have two or three parts and a few 4 or 5. What I can't get is
> >> this, I can't seem to take say two 250Mb videos and make it come
> >> anywhere near 500Mbs when spliced together.
> >
> > This always works for me with avi and mpeg files:
> > mencoder -oac copy -ovc copy -quiet infile1.avi infile2.avi -o
> > outfile.avi
>
> I tried this but it made my video pixelated for some reason. The one I
> tested was a .flv so that may have a LOT to do with it. Maybe it needed
> different options. I tried the man page but it looked like Greek to
> me. I mostly watch videos but no idea on how to make them or even do
> much editing, tho I am sort of learning. My lady friend likes to watch
> videos so I have to put them together and burn them to a DVD.
>
> Things women make us guys do. lol

Hmm ... more likely she decided to keep you busy (quiet) and prove to herself
that you care enough to do things for her? No doubt you let slip that you
like playing with computers ... ;-)

Anyhow, have a look again at the mencoder man page. There's a few settings in
there for video called "extreme" and "insane". You may want to try them.

Alternatively you may find that ffmpeg will do what you want. There's a "copy"
option whereby it just copies the source with zero processing on video or
audio inputs.

--
Regards,
Mick
 
Old 01-04-2012, 02:14 AM
Claudio Roberto França Pereira
 
Default Video editing advice on formats and size of file

Ok, I know what to do. I played a little with ffmpeg and avconv
(ffmpeg's fork, libav, conversion utility) converting 3D YouTube
videos to play at the Nintendo 3DS.
Anyways, I'll pretend you're using ffmpeg, I prefer libav but ffmpeg
is much more common (both are made available by portage, there is
virtual/ffmpeg now). Their syntax is a little different by the way, if
you prefer using libav just look at libav changelog
(/usr/share/doc/libav-version/CHANGELOG.bz2, or something close to
that).

ffmpeg -i file1.avi -i file2.avi -vcodec copy -acodec copy -async 12
-o output.avi

You can use multiple input files, not just 2. If their codec match,
you can copy, if they don't match then you'll need to re-encode the
files (or the just the ones with the different codec).
The -async 12 option do the synchronization trick. The 12 indicates
that ffmpeg should try to correct synchronization at most 12 times per
second. You could use less, try and see the results yourself. I'd say
that even 5 or 3 would give great results, but 12 doesn't seem to
increase file size either.
 
Old 05-03-2012, 11:07 PM
David Haller
 
Default Video editing advice on formats and size of file

Hello,

On Sun, 01 Jan 2012, Mick wrote:
>Anyhow, have a look again at the mencoder man page. There's a few
>settings in there for video called "extreme" and "insane". You may
>want to try them.

I use

-ovc x264 -x264encopts
crf=22:trellis=1:qcomp=0.8:weight_b:8x8dct:subq=6: threads=1:nr=750

or the same with crf=23 for lower quality input and nr=500 (for clean
input). That gives me for DVD MPEG2 input output of the same quality
(and yes, I've looked at very difficult parts of both input and output
basically "frame by frame" while finding those settings

Those settings give quite small files at times, esp. due to the 'nr'
noise reduction filter (which makes files 20-50% smaller with no
visual impact and little impact (<6%) on encoding speed. I get e.g. a
mere 241MiB video track for a 41:19min series-episode in PAL
(720x576@25fps progessive anamorphic (=> 1024x576) with crf=22). The
MPEG2 original is 1.16GiB for the video track...

For me, depending on input, above settings are the "sweet spot"
regarding quality (no difference I can see, either at 1:1 or
fullscreen at 1280x1024 with black bars) and file size.

HTH,
-dnh

--
Never put off till tomorrow what you can avoid all together.
-- fortune file
 
Old 05-03-2012, 11:30 PM
David Haller
 
Default Video editing advice on formats and size of file

Hello,

On Fri, 23 Dec 2011, Michael Mol wrote:
>I'd suggest you give the other tools a try, too. The other tools
>brought up will do essentially the same thing as avidemux; they're
>just ripping the audio and video streams out of the source container
>files and placing them into a new container file.

mkvmerge has the -y option where you can specify

- an offset for a specific track (e.g. delay the audio track by
1000ms)
- and specify a ratio how one track is faster/slower than the other.

For example: I recently had a subtitle track declared as PAL (25fps)
but it was actually NTSC (23.97fps). Additionally, there was an
offset. So, I used:

mkvmerge -o output.mkv --language 1:en input1.avi --language 0:de
-D input_sound2.ac3
-y 0:-7000,23.97/25 subtitle1.srt
| ^^|^^ ^^^^^^^^- delay ratio / skew
| `- absolute offset (-7s)
`- track 0 of the input file (i.e. subtitle1.srt), with the
usual video+audio in one file, it'd be Track 1: for the
audio, use mkvinfo/mediainfo on the input to find out.

(or the other way around resp. PAL/NTCS rates, anyway, according to my
~/.bash_history the above gave me the correct output

By that feature, you can offset one track (e.g. sound or subs) by an
absolute time and skew it at a relative ratio (when one track is
"faster" than the other, usually PAL vs. NTSC or 24fps. Anyway, try
those ratios ,23.97/25 or ,25/23.97 first After determining the
"absolute offset" as early in the file as possible.

When stitching files together, it might be that just one file has that
problem, so, remux that one file with an -y 0ffset,skew into a
temp-file and then append the temp to the other input (or vice versa).

Takes a bit of testing etc., but you should be able to solve all
"stable" desyncronizations.

You're lost if the desync varies over one file (e.g. +1s at the start,
+2 at 25%, in sync at 50%, +3s at 60%, -2s at 75%, +1s at the end...)

HTH,
-dnh

--
> Good. now let's bash PHP. -- Satya
I thought we were talking about programming languages? -- Peter Corlett
 

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