mpeg-ts playback

[Sebastian Dröge]

On Di, 2014-03-04 at 01:05 -0800, Dave Walker wrote:
> I've been attempting to get MPEG-TS content to play back using the Android
> mediacodec decoders. I finally got it working and wanted to report my
> findings and ask a couple questions about how to proceed. My device is a
> Samsung Galaxy S4, and I'm not sure how commonplace this behavior is.
> 
> When I started the audio decoder failed to start. When buffering the first
> frame I got the following from the OMX codec:
> 
> E/SEC_AAC_DEC(  208):  This is unsupported profile in SAACD. Profile 31 is
> not supported
> E/SEC_AAC_DEC(  208):  SAACD only supports AAC-LC Profile
> 
> So, the decoder's confused about profile. Often this data is passed in via
> a 'csd-0' element in the MediaFormat, and sure enough it looks like this
> has helped people in the past. The link below also points out an "is-adts"
> flag in MediaFormat that should be sent to decode ADTS content, which is
> what I have.
> 
> http://stackoverflow.com/questions/18784781/how-to-initialize-mediaformat-to-configure-a-mediacodec-to-decode-raw-aac-data
> 
> I added both csd-0 and is-adts to my MediaFormat, and this shifted around
> the error a bit but ultimately didn't get rid of it. However, if I strip
> out the 7 byte ADTS headers but leave the csd-0 buffer in place to include
> the format parameters, then the content plays fine.
> 
> My question is - how should I best implement this for real? The ADTS format
> is slightly more complicated than a simple 7 byte header, and I'm not sure
> converting from adts->raw is really the business of the amc component. It
> appears that this may be a device-specific foible, and that in general
> devices should support this as long as is-adts is in the format. But my
> device is a super common one - adding a workaround seems reasonable and par
> for the course for the MediaCodec support. In any case the csd-0 element
> will be needed to properly decode ADTS content, and the tsdemux component
> isn't producing the codec data. I assume the correct fix here is to have
> the demuxer create this data as part of its caps.
> 
> Thanks, and apologies in advance for any misunderstandings or mistaken
> terminology. This is my first project in gstreamer.
> 
> Thanks for any advice you can provide.

You could put stream-format=raw on the sinkpad caps of the amc audio
decoder for AAC. Then aacparse could do the conversion to the raw stream
format from ADTS.

I'm not entirely sure if this was already supported in 1.2 or if those
changes to aacparse were added later.

-- 
Sebastian Dröge, Centricular Ltd - http://www.centricular.com
Expertise, Straight from the Source
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