[gst-embedded] GStreamer on TI's embedded platform

Sun Apr 13 13:18:28 PDT 2008

Zhao Liang-E3423C schrieb:
> Vijay,
>  
> I think you can open the log for more information,
> export GST_DEBUG=GST_CAPS:5
>  
> Seems actual adecoder src0 caps is not a subset of src template caps, 
> maybe the src rate, channels, or depth is not suitable for template caps.

This is a programming error in TIs elements. The quite likely set a value in the 
caps which are not in the template caps. Unfortunately you did not send those 
(just as "..."). But there they quite likely forgot e.g. rate or channels.

Stefan
>  
> 
> *Best Regards
> Zhao Liang*
> 
> ------------------------------------------------------------------------
> *From:* Vijay [mailto:vijay.linux.mail at gmail.com]
> *Sent:* Thursday, April 10, 2008 9:38 PM
> *To:* Zhao Liang-E3423C
> *Cc:* gstreamer-embedded at lists.sourceforge.net
> *Subject:* Re: [gst-embedded] GStreamer on TI's embedded platform
> 
> Thanks for your response, Zhao. I really appreciate it. I didn't get a 
> chance to respond to your mail until now.
>  
> I don't think I'm missing a mp3 demux element. Here's why:
>  - This file has worked with every decoder I've tried, without any 
> demuxing or parsing of container format (and I've tried a lot of 
> decoders on a lot of systems! - all without any demuxing)
>  - It has no ID3 or other tags (I removed all such MP3 headers and 
> trailers in the file, myself)
>  - It has only an elementary stream that contains only MP3 frames (each 
> frame starting with "0xFF 0xFB"), all of the same length.
> That means, this file should not require a MP3 parser and any MP3 
> decoder should be able to decode the contents of the file directly.
> Plus, this pipeline comes from Texas Instruments, and they must have 
> tested this before they put it on their website (hopefully)!
>  
> Coming back to the problem I was facing:
> I was wrong about one thing. These are not two problems - it's probably 
> one problem. It can't pause because it probably cannot negotiate caps.
> Here's what gst-inspect says about TI's adecoder plugin:
> 
> Pad Templates:
>   SRC template: 'src'
>     Availability: Always
>     Capabilities:
>       audio/x-raw-int
>              ...
>              ...
>              ...
>   SINK template: 'sink'
>     Availability: Always
>     Capabilities:
>       audio/mpeg
>             mpegversion: { 1, 2, 4 }
>                   layer: { 1, 2, 3 }
>       audio/x-wma
>              wmaversion: { 1, 2, 3 }
>                    rate: { 8000, 11025, 12000, 16000, 22050, 24000, 
> 32000, 44100, 48000 }
>                channels: [ 1, 2 ]
>  
> If I understand this correctly, it means that it takes mp3 or wma audio 
> data as input and gives raw pcm samples as output. Since the filesrc 
> element can output "any" data type, they should match and it should not 
> be a problem. So I'm still stuck and I don't have a clue as to what the 
> problem could be. Please, let me know if you have any idea about this 
> problem. I'd appreciate any help.
>  
> Thanks.
>  
> Vijay
> 
> On Tue, Apr 8, 2008 at 8:20 AM, Zhao Liang-E3423C <E3423C at motorola.com 
> <mailto:E3423C at motorola.com>> wrote:
> 
>     Vijay,
>      
>     I think maybe you miss a mp3demuxe between filesrc and adecoder.
>     and the command shall be
>     gst-launch-0.10 filesrc location=$1 ! mp3demux ! adecoder Codec=3 !
>     osssink
>     TI adecoder element may not accept the filesrc RAW caps.
> 
>     *Best Regards
>     Zhao Liang *
> 
>     ------------------------------------------------------------------------
>     *From:* gstreamer-embedded-bounces at lists.sourceforge.net
>     <mailto:gstreamer-embedded-bounces at lists.sourceforge.net>
>     [mailto:gstreamer-embedded-bounces at lists.sourceforge.net
>     <mailto:gstreamer-embedded-bounces at lists.sourceforge.net>] *On
>     Behalf Of *Vijay
>     *Sent:* Monday, April 07, 2008 8:32 PM
>     *To:* gstreamer-embedded at lists.sourceforge.net
>     <mailto:gstreamer-embedded at lists.sourceforge.net>
>     *Subject:* [gst-embedded] GStreamer on TI's embedded platform
> 
>     Hi,
>     I received TI's port of gstreamer to it's DaVinci processors from
>     http://focus.ti.com/dsp/docs/dspsplash.tsp?contentId=3100
>      
>     I've tried to run the example (scripts) provided by TI and I've
>     faced what seem to be two separate issues.
>     I've copied the stdout log below:
>      
>     <linux prompt>:/opt/system_files_gstreamer# ./test_MP3.sh MP3_file.mp3
>     Setting pipeline to PAUSED ...
>     Pipeline is PREROLLING ...
>     (gst-launch-0.10:1204): GStreamer-WARNING **: pad adecoder0:src
>     returned caps which are not a real subset of its template caps
>     (gst-launch-0.10:1204): GStreamer-CRITICAL **:
>     gst_caps_get_structure: assertion `index < caps->structs->len' failed
>     (gst-launch-0.10:1204): GStreamer-CRITICAL **:
>     gst_structure_get_int: assertion `structure != NULL' failed
> 
>     [program hangs here]
>      
>     For most of you, who don't know about this script: All it does is
>     after setting the gstreamer, plugin and library paths, it runs
>     gst-launch with a pipeline, thus: gst-launch-0.10 filesrc
>     location=$1 ! adecoder Codec=3 ! osssink
> 
>     The two issues I'm facing:
>     (a) The *last* element in the gstreamer pipeline does not reply with
>     a message to the app saying it has paused (This is ascertained with
>     debug prints that I inserted in gst-launch.c. It's possible that for
>     some reason, the element does not pause. I've faced this same issue
>     with pipelines which have no decode/render elements as well.)
>     Actually, I'm not sure if (a) it doesn't pause because it doesn't
>     finish preroll or (b) it says it hasn't finished preroll because it
>     doesn't send a pause signal! (I'm not sure which is the cause and
>     which is the effect).
> 
>     (b) The critical errors printed (seen above. I guess these are
>     caused because of TI's mp3 decoder element plugin.) Could the
>     adecoder capabilities be incompatible? Seems unlikely, since TI
>     would have tested this first.
> 
> 
>     Would anyone know what the issue might be? Has anyone seen a similar
>     issue with gstreamer?
>     I'd greatly appreciate any help.
>     Thanks.
> 
> 
>     Vijay
> 
> 
> 
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