Re: [FFmpeg-user] A/V synchronization problems
>> I had a look and I think it's just that AVI is not >> able to store the sync information. It's a really >> outdated container format, and when I used to use >> it I seem to recall all sorts of problems with AV sync. >Did you try the command line I posted? >It worked fine here... Sadly I just noticed that half of the emails from this mailing list are going into a junk email folder, including your response to this A/V sync issue. >> This e-mail (and any attachments) is confidential >It is really kind that you answer questions here (you >know a lot of things that I don't know) but is there a >chance that you remove this? Fair point. I won't be able to fix that on the corporate mail system, but before I post again I'll work out another way of getting the emails onto the list via a different sending method. This should be the last message with that disclaimer. Regards, Andy Young. http://www.bbc.co.uk This e-mail (and any attachments) is confidential and may contain personal views which are not the views of the BBC unless specifically stated. If you have received it in error, please delete it from your system. Do not use, copy or disclose the information in any way nor act in reliance on it and notify the sender immediately. Please note that the BBC monitors e-mails sent or received. Further communication will signify your consent to this. ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] A/V synchronization problems
Andy Young bbcspp.com> writes: > I had a look and I think it's just that AVI is not > able to store the sync information. It's a really > outdated container format, and when I used to use > it I seem to recall all sorts of problems with AV sync. Did you try the command line I posted? It worked fine here... > This e-mail (and any attachments) is confidential It is really kind that you answer questions here (you know a lot of things that I don't know) but is there a chance that you remove this? Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
Re: [FFmpeg-user] A/V synchronization problems
>I have a problem with A/V synchronization when the source signal is
>disturbed. I am using the following command for transcoding my video:
>
>ffmpeg -y -probesize 600 -threads 1 -i $filename -vf scale=256:144 -b:v
>192k -acodec libmp3lame -b:a 128k -ac 1 -af aresample=async=1000 -ss 0
>-threads 1 -t 3720 -f avi $filename.avi
>
>(I grabbed part of the stream with wget, and it is available on
>https://docs.google.com/file/d/0B86ie_Sd0O9jRlNnYkU5SlkwNnM if you would
>like to play with it on your own, but this is big file, 1.6GB)
>
>At the beginning of the file the synchronization is OK, but after any
>disturbance the audio is going away from video. It is clearly visible that
>about 20 minute of the file the synchronization is broken.
>
>I was trying also with -vsync otions, but it was even worse, or maybe I
>haven't used them in proper way.
>
>Is this possible to make this better? Could you please help me with this
>problem? Thank you!
I had a look and I think it's just that AVI is not able to store the sync
information. It's a really outdated container format, and when I used to use it
I seem to recall all sorts of problems with AV sync.
Just trying Matroska fixes things and you get a better quality encode as it
defaults to x264 instead of MPEG4 for that container format.
I just changed your command a little but didn't seek to improve it, just fix
the xync issue. Presumably you wish to keep the bitrate and frame size very low
for a reason.
ffmpeg -fflags +genpts -i ${filename} -vf scale=256:144 -b:v 192k -acodec
libmp3lame -b:a 128k -ac 1 -f matroska $filename.mkv
The whole file stays in sync right through to the end in that container format.
Take that as a starting point and play from there ...
Regards,
Andy Young.
http://www.bbc.co.uk
This e-mail (and any attachments) is confidential and may contain personal
views which are not the views of the BBC unless specifically stated.
If you have received it in error, please delete it from your system.
Do not use, copy or disclose the information in any way nor act in reliance on
it and notify the sender immediately.
Please note that the BBC monitors e-mails sent or received.
Further communication will signify your consent to this.
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Re: [FFmpeg-user] A/V synchronization problems
Elżbieta Jakubska gmail.com> writes: > I have a problem with A/V synchronization when the > source signal is disturbed. I am using the > following command for transcoding my video: > > ffmpeg -y -probesize 600 -threads 1 -i $filename > -vf scale=256:144 -b:v 192k -acodec libmp3lame > -b:a 128k -ac 1 -af aresample=async=1000 -ss 0 > -threads 1 -t 3720 -f avi $filename.avi I believe the following works fine: $ ffmpeg -i input -vf scale=256:144 -b:v 192 -acodec libmp3lame -b:a 128k -ac 1 -async 1 -ss 0 out.avi This is not a regression, -async 1 was always necessary for such files with reception errors. Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user
