gmane.comp.multimedia.ogg.theora.general

Ogg Theora files player for Windows XP

Maciej Mączyński — 2012-05-14T08:49:43

Hello,

Can anyone help me write Ogg Theora files player in Visual C++ 2008?

I built and added to the CLR Empty Project:
- libogg-1.3.0, libtheora-1.1.1, libvorbis-1.3.2 (http://www.xiph.org/downloads/)
- PortAudio_v19_20111121 (http://portaudio.com/archives/pa_stable_v19_20111121.tgz)
- SDL-1.2.15 (http://www.libsdl.org/release/SDL-devel-1.2.15-VC.zip)

What next? First I would like to play the *.ogv file.

I know that in revision 11431 of Theora (http://svn.xiph.org/trunk/theora) there is splayer.c 
(win32\experimental\splayer\), but when I try to compile it Visual C++ shows many errors. 
Besides this in the revision 11431 there aren't all required libraries (for example ogg, vorbis, PortAudio).

Best regards,
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Re: NHW Image codec - improvement of precision

Raphael Canut — 2012-05-11T17:20:15

Hi again,
Just very quickly, I forgot to add, as I had a request, that I made a
version with more neatness, but I prefer currently more precision, seems
more important.I could add a "neatness parameter" as an encoder option
(rather simple to the contrary of precision setting, file size will be
nearly the same, and encoding/decoding times are the same), but maybe
precision is the really first parameter to improve?
Any advice and comment would be very helpful.
Many thanks for your time,
Raphael

2012/5/11 Raphael Canut <nhwcodec< at >gmail.com>

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NHW Image codec - improvement of precision

Raphael Canut — 2012-05-11T16:11:16

Hello,

Just contact you quickly again, for those interested, I have made a new
version of my codec with a little more precision.This version seems a
little better, -I have updated my demo page: http://nhwcodec.blogspot.com/ -.If
you would have time, any comment (or critics) from the Xiph Community would
be really very appreciated.

(Also I made a previous update to correct a bug, if there would be some
images where my codec bugs, do not hesitate to let me know, would
be also very helpful)...

Many thanks,
Raphael
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Re: png2theora.c + QImage

Gustav González — 2012-04-23T07:15:05

After several days of trials and errors playing with code from many
places, finally I could write a very basic example based on the
png2theora.c file

Here is the code, although it already works it can be enhanced a lot,
so I’m posting these files just for those curious programmers
interested in this specific topic (Qt + libtheora):
http://www.maefloresta.com/portal/files/theora.pro.txt
http://www.maefloresta.com/portal/files/theora.cpp.txt

I hope this can be handy for someone else.

Re: png2theora.c + QImage

Ralph Giles — 2012-04-18T16:01:34


This file is only 304 lines long.


You did see there's already (more accurate) code to do this in
png2theora.c? See rgb_to_yuv in
https://svn.xiph.org/trunk/theora/examples/png2theora.c if you don't
have the latest version.

In particular, decimation isn't the best way to do chroma subsampling. :)


I didn't try compiling your code, but those types should be equivalent
under Qt. Perhaps the corruption is coming from the elsewhere in the
conversion code.

 -r

png2theora.c + QImage

Gustav González — 2012-04-18T02:15:24

Hello there,

I have been working on an alternative version of the png2theora example:
The basic idea is to change the input of the program, using a QImage
[1] variable
instead of a png array.

This is my base file:
http://www.maefloresta.com/tmp/example.cpp

The point where I am stuck starts at this comment:
// LOOK HERE (line 313)

And here is the issue: QImage supports RGB images, so my first task is
to transform
the content of the QImage variable from RGB to YUV.

Here is the code I already use to do the trick with a ffmpeg API and it works:
http://www.maefloresta.com/tmp/rgb2yuv.txt

The function prototype is this:
void RGBtoYUV420P(const uint8_t *bufferRGB, uint8_t *yuv, uint
iRGBIncrement, bool bSwapRGB, int width, int height)

Now, to write a theora frame I'm trying to use the function from the
example (png2theora.c):
static int theora_write_frame(unsigned long w, unsigned long h,
unsigned char *yuv, int last)

So, what is my problem?
In the function RGBtoYUV420P(), my input variable to save the YUV

Re: Development of libtheora 1.2 (Theora 1.2)

Basil Mohamed Gohar — 2012-03-31T12:53:24

Claude,

The libtheora project is not abandoned, but development has slowed down 
in recent months.  However, even as of last night, some code changes 
were being made and tested.  I cannot, however, give you an exact time 
when there will be a release.

Development of libtheora 1.2 (Theora 1.2)

BUP — 2012-03-31T09:18:04

(Mail translated from French)

Hello,

I would like to receive news on the development of libtheora 1.2 (Theora 1.2)

For nothing for 17 months, since the availability of version alpha1.

I ask because I have to choose a codec. And theora 1.2 alpha1 is fine.
But I do not want to use, if it is abandoned.

Thank you in advance for your response.




Claude Beytrison

Re: Wavelet Image Codec - advice

Raphael Canut — 2012-03-26T14:44:35

Hello,
Just contact you quickly again as my last post and questions were not maybe
very precise, and maybe rather vague...
To precise, really hope that my question is relevant on this channel (and
that I am not disturbing you), my approach would be to have a little more
neatness (or sharpness) to the detriment, of course, of precision (at the
same compression ratio).
For example (very quickly), for me Google WebP is a codec that has a very
(very) impressive precision, but on the other hand it maybe tends to
decrease a little neatness (always for me at my very humble level, I am not
an expert).My codec doesn't have this same (impressive) level of precision,
but would have maybe a little more neatness... Would you think this could
be also an "acceptable" approach? Or do you think that precision is the
definitely first "criteria of selection" for an image codec, far above
neatness for example? And that I have to add more precision to my codec,
even if it is to decrease neatness...(My algorithm which is not the

Wavelet Image Codec - advice

Raphael Canut — 2012-03-14T13:11:01

Hello,

Is is a great pleasure to post on a Xiph IRC Channel.I contacted you to
have your advice and comment about wavelets for image/video compression, as
I have made a wavelet-based image compression codec.

I know that currently the best image/video compression codecs use the DCT
block-based transform, like JPEG, Ogg Theora and the recent Google WebP,
for example, but what would you think of wavelet transform?

Here is the link for my wavelet-based image compression codec:
http://nhwcodec.blogspot.com/

I am still trying to improve my codec, and so any comments and advice are
very welcome.I had few, but great discussions with Monty Montgomery and he
also encouraged me to post and present my work on the channel.

Very quickly, the main features would be a fast decoder and maybe a good
neatness.You can find few results on the demo page.You can also download
the win32 binaries to test it. -I am planning to give the source code and
algorithm detail rather quickly, but currently the codec is absolutely not
fin

TheoraPlay - simple Theora playback lib

Kyungjoon Lee — 2012-01-02T10:12:15

Hi, has anybody checked this out?

http://icculus.org/theoraplay/

Quote: TheoraPlay is a simple library to make decoding of Ogg Theora videos easier.

---

It looks like it could be very useful.

Cheers,
Kyungjoon Lee

Re: Newbie Question: Seeking on remote .ogg files (audio)

Chris Pearce — 2011-11-30T21:33:00

Hi Rich,

Take a look at: 
https://developer.mozilla.org/en/Configuring_servers_for_Ogg_media

I suspect your server either is using GZIP compression or doesn't 
correctly support HTTP 1.1 byte range requests.

Regards,
Chris P.


On 1/12/2011 9:05 a.m., Rich Caloggero wrote:

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Re: Newbie Question: Seeking on remote .ogg files (audio)

Basil Mohamed Gohar — 2011-11-30T21:10:57

(Replying to list in addition to you)

I was able to seek in this file without any problem.  I didn't try the
MP3.  I am using Firefox 5.  Can you verify that you're having the
problem with this same file on this server?

On 11/30/2011 03:37 PM, Rich Caloggero wrote:

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Re: Newbie Question: Seeking on remote .ogg files (audio)

Basil Mohamed Gohar — 2011-11-30T20:12:54

Rich,

What version of Firefox were you using?  My understanding is that
Firefox can seek just fine in Ogg Vorbis files, even over the network.  
The problem may reside, however, on the server, if it does not support
range-request headers.  Was the MP3 on the same server as the Ogg file
you were testing with?

P.S.  If the file is something you can provide a link to, that would
make it easier for others to help find the source of the problem.

On 11/30/2011 03:05 PM, Rich Caloggero wrote:

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Newbie Question: Seeking on remote .ogg files (audio)

Rich Caloggero — 2011-11-30T20:05:34

I have vorbis audio files on a remote server.  I want to be able to listen to these files on my local machine using something like winamp.  If I point winamp directly at the file using its url (something like http://www.example.com/file.ogg), the file plays, but is not seekable. If I do the same with .mp3 files, seeking works fine.

I thought this might be a winamp issue, but trying to seek on a remote .ogg file using Firefox’s implementation of html5 audio element also fails; it works fine locally.

What is going on and how can I fix it?

Thanx very much for any info...

Re: Changing frame rate in an ogg

Ralph Giles — 2011-08-25T21:51:03


Two things:

Theora is strictly fixed frame rate. If the incoming video data is not
at a fixed frame rate, then your encoder will need to check against
the playback clock and duplicate or drop frames to make it so. Since
RTP has per-packet timestamps, this can be relaxed to simplify the
sender implementation, but once saved to an Ogg file, all players will
treat the stream as fixed frame rate. This is likely the reason your
file doesn't behave as you expect.

If you just want to adjust the frame rate of an already saved file,
you could try the little 'rogg_theora' utility I wrote.

  http://downloads.xiph.org/releases/rogg/rogg-0.4.tar.gz

Be aware that it doesn't support Ogg chains or files over 2 GB on 32
bit systems.

 -r
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Changing frame rate in an ogg

Stefano Luceri — 2011-08-25T11:57:25

Hi

 

I'm trying to understand how to change framerate in an ogg/theora file. I'm
recording a stream from a chat (RTP/THEORA) but frame rate of recorded
stream is not correct.

Reading theora documentation it seems that frame rate (FRN and FRD) only
affects granulepos/timestamp but changing it (manually) in the ogg files
causes bad decoded frames while playing (I've also tried other ogg videos).

Obviously I'm missing something, is there some way to change frame rate (I
need to slow the playing of file) using ogg or oggz api?

 

Thank you,

 

Stefano




 

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Re: Ripping theora stream

Stefano Luceri — 2011-08-19T10:45:18

The problem of fast playing was a fault in writing down the packets. I set
up granulepos = 0 for all packets, most players didn't even open the file,
only mplayer open/play the file ad maximum speed.

I solved the problem checking if a packet is a keyframe using:

th_packet_iskeyframe(&op)

and adjusting consequently granulepos.

Such solution is not very fast but the ogg file produced seems to be ok and
seekable.

Stefano



rate and see if it is correct.  One possibility is that the transmitter is
lying to >you about the frame rate.  Another possibility is that some frames
are getting lost (RTP is a lossy protocol).  When a frame is lost, you
should probably insert >an empty (size 0) packet in the Ogg stream so that
you don't lose temporal synchronization.


already).

Re: Reading audio data from an .ogv video

Chris Pearce — 2011-08-17T22:02:45

Chris Double has a blog post outlining A/V sync in a simple ogg player:
http://www.bluishcoder.co.nz/2009/06/27/playing-ogg-files-with-audio-and-video.html

If you're interested I took his code and added seeking support, and it's 
available here:
https://github.com/cpearce/plogg
(There are a few bugs in the seeking code I've not fixed, but it works 
most of the time).


Chris Pearce.

On 18/08/2011 8:48 a.m., Ralph Giles wrote:

Re: Reading audio data from an .ogv video

Ralph Giles — 2011-08-17T20:48:20


Sounds like you're reading the audio data correctly, and the problem
is just in your synchronization code. Sound cards generally don't have
very accurate clocks, so you need to schedule video playback based on
the audio playback clock. For example, keep track of how often the
audio engine requests a new playback buffer and update the visible
video frame based on that.

HTH,
 -r

Reading audio data from an .ogv video

Nuno Moreira — 2011-08-17T18:10:08

I need some info on how can I read the audio data from an .ogv video.  
I'm creating an in-game player and so far I'm only able to read and render the frames of the video (no audio). Tried splitting the video from the sound but it got out of synch really quickly. 
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