[gst-devel] encode / decode chain didn't work

[Wim Taymans]

On Mon, 2008-09-01 at 18:11 +0530, Sachin Pandhare wrote:
> Hi,
> i was testing basic encode and decode chains.
> 
> gst-launch videotestsrc ! ffmpegcolorspace ! theoraenc ! filesink
> location=/test_theoraenc.bin

> this created a file.  then i tried
> 
> gst-launch filesrc location=/test_theoraenc.bin ! theoradec !
> ffmpegcolorspace ! xvimagesink
> 
> but this gave me following error:
> --------------------------------------------------------------------------------------------------
> ERROR: from element /pipeline0/theoradec0: Could not decode stream.
> Additional debug info:
> theoradec.c(1166): theora_handle_data_packet
> (): /pipeline0/theoradec0:
> no header sent yet
> --------------------------------------------------------------------------------------------------
> 
> was there any mistake in my commands?

yes, theora is a format that should be encapsulated into a container
such as ogg, like this:

gst-launch videotestsrc ! ffmpegcolorspace ! theoraenc ! oggmux !
filesink location=/test_theoraenc.ogg

and to play it back: 

gst-launch filesrc location=/test_theoraenc.ogg ! oggdemux ! theoradec !
ffmpegcolorspace ! xvimagesink

The reason is that theora relies on the container format to feed it
exactly one encoded frame, there are no fame markers in the raw theora
bitstream otherwise.

Wim
> 
> 
> Thanks,
> Sachin
> 
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