Vob to flv

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Vob to flv

jackyr

Hi

I am encoding from VOB to FLV flash
 using -f flv or -vcodec h263 it works fine
I have 3 questions  

 1- one pass is giving better quality than 2 passes
    someboby knows what ?

 2- is there a way to encode to on2 VP6 or VP6f
    using the pre compiled windows version ?

 3- if not 2: is there some command line args
    whith give almost same results with -f flv
    than on2 VP6 ?

thanks for your insights  

jackyr  
 

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Re: Vob to flv

James Darnley
2009/12/30 jacky <[hidden email]>:
>
>  1- one pass is giving better quality than 2 passes
>    someboby knows what ?
>
No, because you haven't given us your command lines.  You could be
using the first-pass output video as the second-pass input video. (You
shouldn't do that)  Perhaps you have mistakenly used a lower bitrate
on the 2-pass encode

>  2- is there a way to encode to on2 VP6 or VP6f
>    using the pre compiled windows version ?
>
You can't with any version of ffmpeg, because it does not have a VP6 encoder

>  3- if not 2: is there some command line args
>    whith give almost same results with -f flv
>    than on2 VP6 ?
>
If you don't have a technical reason for not using H.264 then you can
use libx264 for the video encoding.  Then it is simple:
ffmpeg -i file.flv -vcodec libx264 -vpre hq -threads 0 -crf 23 [audio
options] out.flv

If -vpre hq is too slow, then replace it with -vpre default.  If that
is still too slow, use -vpre normal
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RE : Vob to flv

jackyr
Thanks for answering


-----Message d'origine-----
De : [hidden email]
[mailto:[hidden email]] De la part de James Darnley
Envoyé : mercredi 30 décembre 2009 13:19
À : FFmpeg user questions and RTFMs
Objet : Re: [FFmpeg-user] Vob to flv



2009/12/30 jacky <[hidden email]>:
>
>  1- one pass is giving better quality than 2 passes
>    someboby knows what ?
>
>No, because you haven't given us your command lines.  You could be using
the first-pass output video as the second-pass input video. (You shouldn't
do that)  Perhaps you have mistakenly used a lower bitrate on the 2-pass
encode

The commande lines are
  f_in is the VOB file ,   f_out is the flv file
  ffmpeg -i %f_in% -pass 1 -f flv -b 400k -r 12.5 -s 720x576 -y %f_out%
  ffmpeg -i %f_in% -pass 2 -ar 22050 -ac 1 -acodec libmp3lame -ab 48k -f flv
-b 400k -r 12.5 -s 720x576 -y %f_out%

>  2- is there a way to encode to on2 VP6 or VP6f
>    using the pre compiled windows version ?
>
>You can't with any version of ffmpeg, because it does not have a VP6
encoder

Clear enough

>  3- if not 2: is there some command line args
>    whith give almost same results with -f flv
>    than on2 VP6 ?
>
>If you don't have a technical reason for not using H.264 then you can use
libx264 for the video encoding.  
>Then it is simple: ffmpeg -i file.flv -vcodec >libx264 -vpre hq -threads 0
-crf 23 [audio options] out.flv


I have a technical reason today  
 the RED5 based server which will borrow from an university does not support
h.264 coding
 later we will have ours with a proper RED5 version and I expect the H.264
will be
 supported

As far I know Adobe is using file extension F4V for H.264 and FLV for VP6
 I still have trouble to figure out what will append in the future ? Do you
know ?
 Is there any problems using FLV for H.264 encoding ?

   
 
 

If -vpre hq is too slow, then replace it with -vpre default.  If that is
still too slow, use -vpre normal
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Regards
jacky

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Re: RE : Vob to flv

James Darnley
>>  1- one pass is giving better quality than 2 passes
>>    someboby knows what ?
>>
>>No, because you haven't given us your command lines.  You could be using
> the first-pass output video as the second-pass input video. (You shouldn't
> do that)  Perhaps you have mistakenly used a lower bitrate on the 2-pass
> encode
>
> The commande lines are
>  f_in is the VOB file ,   f_out is the flv file
>  ffmpeg -i %f_in% -pass 1 -f flv -b 400k -r 12.5 -s 720x576 -y %f_out%
>  ffmpeg -i %f_in% -pass 2 -ar 22050 -ac 1 -acodec libmp3lame -ab 48k -f flv
> -b 400k -r 12.5 -s 720x576 -y %f_out%
>
What was the command you used for the 1-pass encode?  Or did you just
look at f_out from the first pass?

> I have a technical reason today
>  the RED5 based server which will borrow from an university does not support
> h.264 coding
>  later we will have ours with a proper RED5 version and I expect the H.264
> will be
>  supported
>
> As far I know Adobe is using file extension F4V for H.264 and FLV for VP6
>  I still have trouble to figure out what will append in the future ? Do you
> know ?
>  Is there any problems using FLV for H.264 encoding ?
>
That is a good reason.

I don't know what Adobe suggests for extensions but IMHO using f4v is
not correct.  Flash should have no problem with H.264 video in an FLV
container.
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RE : RE : Vob to flv

jackyr


-----Message d'origine-----
De : [hidden email]
[mailto:[hidden email]] De la part de James Darnley
Envoyé : mercredi 30 décembre 2009 14:42
À : FFmpeg user questions and RTFMs
Objet : Re: [FFmpeg-user] RE : Vob to flv



>>  1- one pass is giving better quality than 2 passes
>>    someboby knows what ?
>>
>>No, because you haven't given us your command lines.  You could be
>>using
> the first-pass output video as the second-pass input video. (You
> shouldn't do that)  Perhaps you have mistakenly used a lower bitrate
> on the 2-pass encode
>
> The commande lines are
>  f_in is the VOB file ,   f_out is the flv file
>  ffmpeg -i %f_in% -pass 1 -f flv -b 400k -r 12.5 -s 720x576 -y %f_out%
>  ffmpeg -i %f_in% -pass 2 -ar 22050 -ac 1 -acodec libmp3lame -ab 48k
> -f flv -b 400k -r 12.5 -s 720x576 -y %f_out%
>
What was the command you used for the 1-pass encode?  Or did you just look
at f_out from the first pass?

My command lines are following if I assume
 f_in is the VOB file ,   f_out is the flv file
 **first pass
    ffmpeg -i %f_in% -pass 1 -an -f flv -b 400k -r 12.5 -s 720x576 -y
%f_out%
 **second pass
    ffmpeg -i %f_in% -pass 2 -ar 22050 -ac 1 -acodec libmp3lame -ab 48k //
                             -f flv -b 400k -r 12.5 -s 720x576 -y %f_out%

All parameters are the same except sound is stopped
Same inputs for the 2 passes , same output , I assume the second pass
Is reading the same input but get some infos from the pass1_log file
Am I right ?



> I have a technical reason today
>  the RED5 based server which will borrow from an university does not
> support h.264 coding
>  later we will have ours with a proper RED5 version and I expect the
> H.264 will be
>  supported
>
> As far I know Adobe is using file extension F4V for H.264 and FLV for
> VP6
>  I still have trouble to figure out what will append in the future ? Do
you
> know ?
>  Is there any problems using FLV for H.264 encoding ?
>
That is a good reason.

I don't know what Adobe suggests for extensions but IMHO using f4v is not
correct.  Flash should have no problem with H.264 video in an FLV container.
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