Sound desynchronisation, resampling and duration

Dear all,

I use Kdenlive 0.6 svn video editor, based on MLT and ffmpeg. The result
is great and will probably compare to professional solutions. 

I can only complain from :

* Frequent sound desynchronisation. Sometimes 0.1 or 0.2 seconds, but it
can be seen and heard. 
* Poor sound resampling. Especially when playing low sample rates (8.000
hz) at higher bitrates (48.000 hz).
* Sometimes the duration of a video is not correct and does not
correspond to the duration of stream.

I guess this is a know problem and I hope that these issues can be
adressed in a short term future. 

In video editing, accuracy is very important, as for duration,
synchronisation and resampling. Continue the good work. 

Kind regards,
Jean-Michel

I have heard of "Simple Profile Level 0" for MPEG-4, can FFmpeg encode this kind of file?

Can anyone tell me what these options mean in FFmpeg?

-profile           <int>   E.VA.
   unknown               E.VA.
   aac_main              E..A.
   aac_low                E..A.
   aac_ssr                E..A.
   aac_ltp                 E..A.
-level             <int>   E.VA.
   unknown               E.VA.

Thanks

How could I make video play loop or stop at last frame while audio still finished.

I am newbie of ffmpeg and want to combine video with audio , or image with audio and I could do it now

After I combine video and audio to be one file, my video is shorter than my audio and I want make it to play again
or stop at last frame if my audio still not play finished.  Now my result is about video showing white page
when it is end before audio play finished. How could I solve this problem?

Thanks 

bubbleball
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Re: converting camstudio with color problems

Tom wrote:
> Dear ffmpeg experts,
>
> I have a screencapture video with camstudio losless codec
> and I'd like to convert to flv (or any other videoformat compatible
> with flash video encoder).
> The result in all cases is the same: the colors are off a little bit.
> I tried flv and flashsv codec also.
>
> The output:
>
> ffmpeg -i colors.avi -vcodec flashsv colors_mod2.flv
> Seems stream 0 codec frame rate differs from container frame rate: 200.00 (200/1
> ) -> 58.00 (58/1)
> Input #0, avi, from 'colors.avi':
>   Duration: 00:00:01.8, start: 0.000000, bitrate: 2729 kb/s
>   Stream #0.0: Video: camstudio, rgb555, 710x228, 58.00 fps(r)
>   Stream #0.1: Audio: pcm_s16le, 44100 Hz, stereo, 1411 kb/s
> File 'colors_mod2.flv' already exists. Overwrite ? [y/N] y
> Output #0, flv, to 'colors_mod2.flv':
>   Stream #0.0: Video: flashsv, bgr24, 710x228, q=2-31, 200 kb/s, 58.00 fps(c)
>   Stream #0.1: Audio: libmp3lame, 44100 Hz, stereo, 64 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> Press [q] to stop encoding
> frame=  109 fps= 52 q=0.0 Lsize=     508kB time=1.9 bitrate=2215.3kbits/s
> video:490kB audio:15kB global headers:0kB muxing overhead 0.612583%
>
> This shows the difference: http://futourist.hu/colors.jpg

Re: converting camstudio with color problems

>> This shows the difference: http://futourist.hu/colors.jpg
>> This is the SVN-r9767 version under windows.
>> Is there any solution for this color problem?

> your ffmpeg version is too old.
> also, can you provide your input file ?

Yes, of course: http://futourist.hu/colors.avi
I've tried with rev10141 with the same result.
But now I've found rev10214 win32 build and
it seems the colors are right.
Wonderful.

thx/Tom

--

-- 
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Choose Python.

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Re: I have heard of "Simple Profile Level 0" for MPEG-4, can FFmpeg encode this kind of file?

tandangdang a écrit :
> Can anyone tell me what these options mean in FFmpeg?
> 
> -profile           <int>   E.VA.
>    unknown               E.VA.
>    aac_main              E..A.
>    aac_low                E..A.
>    aac_ssr                E..A.
>    aac_ltp                 E..A.
> -level             <int>   E.VA.
>    unknown               E.VA.

With -level / -profile, you can force mpeg4 (h264 ?) specifications. You 
can find more informations about level/profile here :
http://www.m4if.org/resources/mpeg4userfaq.php#Profiles

With FFmpeg, you can make Mpeg4 ("-vcodec mpeg4") :
- Simple Profile level 0, using "-profile 0 - level 8"
- Simple Profile level 1, using "-profile 0 - level 1"
- Simple Profile level 2, using "-profile 0 - level 2"
- Advanced Profile level 4, using "-profile 15 - level 4"

and surely more 

--

-- 
Julien YOUX
.             ////          .
              (. .)
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Re: converting camstudio with color problems

> But now I've found rev10214 win32 build and
> it seems the colors are right.
> Wonderful.

Unfortunately this was early happiness.
Although the colors are right,
the voice is missing and a second version of my testing 
video is strange enough after the conversation. 
The rows are shifting...
http://futourist.hu/colors2.avi

thx/Tom

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Re: I have heard of "Simple Profile Level 0" for MPEG-4, can FFmpeg encode this kind of file?

Le septidi 17 fructidor, an CCXV, tandangdang a écrit :
> Can anyone tell me what these options mean in FFmpeg?
> 
> -profile           <int>   E.VA.
>    unknown               E.VA.
>    aac_main              E..A.
>    aac_low                E..A.
>    aac_ssr                E..A.
>    aac_ltp                 E..A.
> -level             <int>   E.VA.
>    unknown               E.VA.

Some codec standards defines "profiles" and/or "levels", which are subsets
of the codec suited for particular uses. For example, AAC defines a "low"
profile, which can be read with approximatively as much CPU power as MP3,
while the "main" profile is more expensive (but better quality, of course).

-profile and -level are options to tell ffmpeg to use a profile or a level
for its encoding. It only works if the codec implementation supports it.

aac_main and cie. are symbolic constants for the -profile option to name AAC
profiles. Obviously, the fact that they exist show that the codec
implementation supports them, although SSR is currently not implemented.

Regards,

--

-- 
  Nicolas George

Syncing of mpg and mp3

Hi,
I have recorded a video session using xvidcap with sound disabled to 
reduce frame skipping when the processor becomes busy.
The sound was recorded on a notebook in parallel so I end up with a mp3 
and mpg file. I want to merge them with ffmpeg into one.
The problem is even though I hit start and stop recording on the two 
machines simultaneously, due to framedrop of xvidcap, the video
ends up much shorter than the audio so I would like to have the video 
linearly scaled so the resulting new video is as long as the audio
with the actions in the video coinciding with the audio. I have tried 
with ffmpeg but have run out of options. Any help will be appreciated.
Thanks
Tiaan

Re: Syncing of mpg and mp3

Tiaan Wessels a écrit :
> Hi,
> I have recorded a video session using xvidcap with sound disabled to 
> reduce frame skipping when the processor becomes busy.
> The sound was recorded on a notebook in parallel so I end up with a mp3 
> and mpg file. I want to merge them with ffmpeg into one.
> The problem is even though I hit start and stop recording on the two 
> machines simultaneously, due to framedrop of xvidcap, the video
> ends up much shorter than the audio so I would like to have the video 
> linearly scaled so the resulting new video is as long as the audio
> with the actions in the video coinciding with the audio. I have tried 
> with ffmpeg but have run out of options. Any help will be appreciated.
>   

Hi,
If your video is much shorter, try to cut it with the same length of 
your mp3 (ffmpeg -i file.mpg -vcodec copy -t num_of_seconds_of_mp3 
final.mpg), then mux the mp3 and final.mpg.

--

-- 
Julien Youx

.           ////            .
           (. .)
-------oOO--(_)--OOo---------
http://www.nain-de-jardin.com