Displaying 20 results from an estimated 4000 matches similar to: "AW: How to get the duration of a file or track?"
2007 Feb 16
1
AW: How to do Theora playback efficiently ?
Hi Ralph,
thanks for your posting.
Yes, the standard example player in the theora distribution could also do it
when theora would not need so much time. I removed the frame dropping from
the example because it's based on some audio stuff under Linux that isn't
available on Windows. Currently I've no frame dropping handling build in
because the first goal is a good raw performance of
2007 Nov 23
2
Controlling the vorbis encoder precisely
Hello,
currently I'm working on a vorbis based encoder that adds multiple single wave sounds into one vorbis stream (and put every sound in one or more ogg pages). During the process an index is written in an extra file so later you can locate a sound's position easily by a file position and length value.
The problem is the sample-exact separation between those encoded wave sounds: If I
2008 Dec 04
3
ogg dirac granulepos in oggz tools
2008/11/26 David Flynn <davidf+nntp at woaf.net>:
>>>> http://trac.annodex.net/changeset/3801
>>>
>>> I'll test this shortly.
>
> Ok, i've tested muxing some audio and video together and that works fine.
> woo.
great, thanks :-)
So the last remaining tool to check is oggz-chop. I at first assumed it
would not work with Dirac's granulepos,
2004 Sep 22
3
copying an ogg stream
dear list,
i am trying to write a small program which reads an ogg file and writes
it to another ogg file (and changes serial number, granulepos etc on the
fly).
reading the ogg file is ok (ogg_sync_pageout, ogg_stream_pagein,
ogg_stream_packetout). but writing the file doesn't work - the
granulepos and page structures don't match with the original file.
here's what i am doing.
2008 Nov 03
0
No subject
4) Subtract 1 from the keyframe, then repeat step 3).
5) Begin reading from the frame discovered in step 4. Drop any packets
which are output on the first page. Count down until we reach the
keyframe, dropping packets until then.
6) Continue counting down until we reach the target frame, we are now
decoding each frame/packet. At the target frame produce the YUV
output.
You can see this in code
2008 Nov 03
0
No subject
4) Subtract 1 from the keyframe, then repeat step 3).
5) Begin reading from the frame discovered in step 4. Drop any packets
which are output on the first page. Count down until we reach the
keyframe, dropping packets until then.
6) Continue counting down until we reach the target frame, we are now
decoding each frame/packet. At the target frame produce the YUV
output.
You can see this in code
2007 Aug 23
2
How to get the duration of a file or track?
I'm starting with the theora player_example.c. I want to be able to
determine the duration of the audio/video ahead of time, to be able to
display it somewhere.
I can't see anything obvious in ogg.h, theora.h, or vorbis.h for this.
Can anyone help me with the right place to look to do this?
Thanks,
Ken Larson
FMJ project, fmj.sourceforge.net
2009 Feb 16
2
Theora packets with granulepos of -1
Hello,
I'm just totally confused. In my theora streams encoded using ffmpeg2theora (but also when using my own encoder) I have packets with a granulepos of -1 so I can't identify the packet during a seeking operation correctly. I can also see those strange value when I just print the packet granulepos before sending it to the Theora decoder.
I know why there are PAGES with granularpos of
2008 Nov 13
5
ogg dirac granulepos in oggz tools
Hi,
I'm wondering if the Dirac granulepos parsing in liboggz and display
in the oggz tools is currently correct, as I'd like to do a release of
these soon.
A couple of days ago David Schleef mentioned there were some problems.
David, is that currently true (ie. since David Flynn's recent updates
to support Dirac), and if so could you please explain what the
problems are, or point me
2008 Feb 13
2
Header packet multiplicity
> There are a usually lot more data packets than header packets, so
> having an internal length there hurts your bitrate a lot more. Of
> course, it may not be significant for an uncompressed text codec.
If muxed with a video, it's insignificant (well, for my test cases).
> With codecs using the 'count of decodable samples' rule to calculate
> their granulepos, the
2008 Nov 21
6
ogg dirac granulepos in oggz tools
2008/11/21 David Flynn <davidf+nntp at woaf.net>:
> On 2008-11-21, Conrad Parker <conrad at metadecks.org> wrote:
>> 2008/11/15 David Flynn <davidf+nntp at woaf.net>:
>>> On 2008-11-14, Conrad Parker <conrad at metadecks.org> wrote:
>>>> It seems oggz chop, merge and sort will need some attention to deal
>>>> with the Dirac
2002 Sep 16
2
AW: Keyframe seeking in Ogg and spec
Hi all,
> One problem I see with your proposed implementation is that it does
not
> specify how audio and video would be synchronized, since there are no
> absolute time stamps for the video frames. So it is difficult to
account
> for
> audio latency on different systems, much like when you play an AVI
file.
> Ideally it would be wonderful to have timestamps that could be used
2008 Nov 13
1
[Schrodinger-devel] ogg dirac granulepos in oggz tools
On Thu, Nov 13, 2008 at 06:06:10PM +0900, Conrad Parker wrote:
> A couple of days ago David Schleef mentioned there were some problems.
> David, is that currently true (ie. since David Flynn's recent updates
> to support Dirac), and if so could you please explain what the
> problems are, or point me to a bugtracker where they are reported. eg.
I mostly meant what you apparently
2009 May 04
1
[PATCH] oggz: inefficient seeking
I have a 1.1G Ogg file with vorbis and theora. oggz_seek_units() takes 14
seconds to find a position in the file towards the end. Now, the function
guess() in oggz_seek() guesses a position at about 1.5G and then slowly
searches back until it finds the end of the file (continously seeking
beyond the end of the file and then calling read which returns 0). Then
it does a linear scan from the
2008 Nov 10
2
oggz-validate does not seem to check for correctly framed headers
While testing the new vcut, some of the early results had badly framed
headers. I actually didn't notice it at first, because I was testing
with oggz-validate, but ogginfo does identify the problem:
"WARNING: Vorbis stream X does not have headers correctly framed.
Terminal header page contains additional packets or has non-zero
granulepos"
Conrad (or someone else) may want to
2008 Feb 27
2
Re: Updating the Ogg mapping for Dirac
On 28/02/2008, Ralph Giles <giles@xiph.org> wrote:
> Conrad had suggested instead extending the now Ogg-specific initial
> data to include the framerate (and possibly also frame size) since
> these are somewhat tedious to parse out of the sequence header. It
> turns out that gstreamer (the test framework everyone's been using
> with schroedinger) was already
2007 Nov 26
2
AW: Controlling the vorbis encoder precisely
Ok, related to the replys from Eric and Monty there are 3 possible solutions
- 1. use lossless encoding like FLAC
- 2. insert large chunks of silence between the wave sounds
- 3. use completely seperate chained streams
-> 1. Flac can't be used because of disk space and bandwidth limitations.
-> 2. I also tried this variant but in that case my sounds don't start immediately
2004 May 18
4
granulepos start/end revisited
Hi all,
I noticed the following Subversion commit today:
r6719 | xiphmont | 2004-05-18 16:04:53 +1000 (Tue, 18 May 2004) | 11
lines
Updated doc to reflect current proposal...
Not as much a proposal at this point actually; this is the way I'm now
implementing it. Although we're still in the 'RFC'/'look for horrible
lossage' stage, this is close to being
2008 Feb 19
4
non-decreasing granulepos
Hi all,
something which came up recently in relation to the design of Kate's
granulepos was whether or not the granulepos of successive Ogg pages
is allowed to be the same, ie. whether or not granulepos must be
strictly increasing.
As this question is more generally about Ogg granulepos, how about we
answer it first and then get back to the discussion of Kate's
granulepos ...
Here is
2003 Nov 15
2
some more granulepos questions
I've made a lot of progress on my lossless Vorbis editing project. I
have a few more questions about granulepos issues I don't quite
understand.
granulepos is a property of Ogg pages, yet it is a field in the
ogg_packet struct. When reading packets from an Ogg stream, the
granulepos is set to -1 for all packets except the last packet in a
page. From this I infer that
- for encoding,