VLC player is not properly recording streamed MPEG files

*nix specific usage questions
Rahul_Shukla
New Cone
New Cone
Posts: 5
Joined: 29 Sep 2005 13:09

VLC player is not properly recording streamed MPEG files

Postby Rahul_Shukla » 30 Sep 2005 14:55

I am streaming an MPEG file using VLC and recording it at the receiving end using another VLC using similar HTTP protocol and similar parameters at both end.
I have streamed file 3 times and each time the size of recorded file is different. Am I incurring some n/w losses on HTTP connection? What is the reason behind this mis behavior.
Whether Encapsulation format and chosen protocol UDP/HTTP can affect the receiving VLC's behavior for recording a file.
Any help is welcome..
Rahul
PS: This behavior holds true for both windows and Linux..
Rahul

The DJ
Cone Master
Cone Master
Posts: 5987
Joined: 22 Nov 2003 21:52
VLC version: git
Operating System: Mac OS X
Location: Enschede, Holland
Contact:

Postby The DJ » 01 Oct 2005 15:11

VLC remuxes the file when saving it, so in theory it could be different each time.
Don't use PMs for support questions.

Rahul_Shukla
New Cone
New Cone
Posts: 5
Joined: 29 Sep 2005 13:09

Postby Rahul_Shukla » 03 Oct 2005 05:01

Hi,
Could you please explain the role of encapsulation format used at Transmit and receive side.
I guess first input video file is formatted according to encapsulation format such as MPEG-TS and then it is adapted for given protocol such as UDP, HTTP. At the receive side, first it remove Protocol's header information and create encapsulated stream such as MPEG-TS and then what operations VLC will perform further?
I am still not clear about this remuxing business. Could you please describe a bit more.
Thanks for your help
Rahul

The DJ
Cone Master
Cone Master
Posts: 5987
Joined: 22 Nov 2003 21:52
VLC version: git
Operating System: Mac OS X
Location: Enschede, Holland
Contact:

Postby The DJ » 03 Oct 2005 16:45

VLC then receives the stream, removes the protocol information, then reads the MPEG-TS streamformat and creates Elementary Streams (video/audio only) out of it. When you again save this, VLC wraps these ES into a new MPEG-TS stream.

So you get MPEG-PS -> ES -> ES in MPEG-TS -> MPEG-TS in UDP/HTTP on the sending side,
and MPEG-TS in UDP/HTTP -> MPEG-TS -> ES -> ES in new fileformat on the receiving side.

Add packet loss to that on the network, and you see how the files will never be the same.
Don't use PMs for support questions.

Rahul_Shukla
New Cone
New Cone
Posts: 5
Joined: 29 Sep 2005 13:09

Postby Rahul_Shukla » 04 Oct 2005 10:44

That means, during capturing/remuxing it loses out ES corresponding to non audio-video channels such as Teletext etc. Then it will also loose out numerous stream related information contained in MPEG-4. What happens to BiFS stream of MPEg-4 and suppose if I have put some other type of data in MPEG-4 file.
Thanks
Rahul
PS: Could you suggest other streaming server/client applications which can capture everything on transmission. Will "mpeg4ip" will be of any help.
Rahul


Return to “VLC media player for Linux and friends Troubleshooting”

Who is online

Users browsing this forum: No registered users and 37 guests