[gst-embedded] Gstreamer Demuxers
ensonic at hora-obscura.de
Mon Aug 18 13:30:19 PDT 2008
Michael Smith schrieb:
> On Wed, Aug 6, 2008 at 8:08 PM, gulshan karmani
> <gulshan.karmani at gmail.com> wrote:
>> Hi All,
>> I have some questions regarding Gstreamer Based Demuxers used
>> inside poky for media playback,
>> 1. While using 'avidemux' as a demuxer plugin we get continuous
>> 'Alignment Traps'
>> which is affecting the audio quality. We have a cmdline option to tell
>> the kernel to fix these traps and suppress the warning but this could
>> be just a workaround.
>> Is this alignment trap caused by demuxer ? Or we need to take care of something
>> in lower layers ?
>> Instead of avidemux if we use 'ffdemux_avi' we do not get these traps.
> I assume this is something doing unaligned multibyte reads? It's quite
> possible that this is something in avidemux - not exactly a bug, but
> code that could be improved.
> If you can fix it, we'd certainly include your patches in future versions.
>> [We use Gst-omx decoders below which are calling ffmpeg for decoding,
>> ffmpeg has been hardware accelerated].
>> 2. Which are the Stand-alone Aac and mp3 demuxers inside Gstreamer to be used ?
>> We are trying to use ffdemux_mp3 for mp3 and getting some package
>> building issues.
> Do not use that. mp3parse is the appropriate element for parsing mp3
> bitstreams. It should get autoplugged.
>> While for Aac we tried gst faad but this is being identified as Aac
>> decoder along with parser. Could we not use this plugin just as a
>> demuxer ?
> No. Currently, I don't think there's a raw AAC bitstream parser in
> gstreamer. If you could contribute one, that would be very welcome -
> quite a few people have asked for it. Basing this on mp3parse might be
> a good idea - there's probably lots of things that would be similar.
Nokia will contribute a aacparser based on baseparse real soon.
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