Smart, Gary schrieb:
-----Original Message-----
From: [email protected] [mailto:libav-user-
[email protected]] On Behalf Of Vladimir Eremeev
Sent: 17 September 2009 11:48
To: [email protected]
Subject: Re: [libav-user] Concatenating movie files - duration not
updated
Smart, Gary wrote:
and dumping them into the output file. It then repeats this,
dumping
the packets out with pts values adjusted such that they continue on
from
the first block. The output file is then closed normally using the
ffmpeg libav functions.
You also should adjust DTS.
Do you use av_write_frame or av_interleaved_write_frame?
I'd use the first one, with correct adjusting DTS and PTS.
Smart, Gary wrote:
1) The resultant file, while clearly twice the size, seems to
contain
the same 'duration' as the original file!
How did you check this?
Smart, Gary wrote:
What do I need to do to ensure that
ffmpeg writes the new duration (twice as long) into the new file?
In case of MPEGTS the duration is not stored in the file. This is a
'headless' format, it is designed to make it possible for the client
to
connect to it from any point.
FFmpeg calculates the duration. It looks at the timestamps in the
beginning
and in the end, and subtracts one from another.
Smart, Gary wrote:
2) I notice that closing the avFormat seems to take an awful long
while?
Is ffmpeg scanning the whole file in order to write the trailer or
something?
This is the first sign that something is wrong.
In your case, most probably, this means that libav* has stored a lot
of
packets in memory and now interpolates their timestamps and writes to
disk.
Smart, Gary wrote:
p.s. if anyone thinks they can help, I will happily send them the
source
code (not very long at all).
You could post it here.
OK - thanks for that. The problem did indeed appear to be dodgy dts
values.
However - now that I can create a file twice the size and play it from
one end to another successfully, I am still wondering why it takes
nearly 2 minutes to close the file (a 10 minute long ts file). i.e. the
url_fclose call takes nearly 2 minutes!
Do you use av_write_frame() or av_write_interleaved_frame()?
The second form would buffer packets as it sees fit.
Best regards,
-Stephan
_______________________________________________
libav-user mailing list
[email protected]
https://lists.mplayerhq.hu/mailman/listinfo/libav-user
