Problems with Dolby Audio and typefind

Neil Jones neiljay at
Thu Dec 6 06:52:54 PST 2012


Im having issue with typefind correctly detecting Dolby audio.


If im using a normal big-endian ac3 file then typefind works, but if I try
capturing AC3 from a spif input the data is little-endain and has big
chunks of zeros in it (as its transported as 2 channel 48Khz 16bit PCM
accross spdif), typefind and aacparse fail to recognise this audio, if i
manually pipe this audio into my decoder (with out gstreamer) it plays it
fine. Should typefind / aacparse be able to deal with this data ? I had
considered writing an iec958-src component which detect the incoming data
type PCM / AC3/ DTS and strips out the zeros, has anyone done anything like
this ?


I cannot get typefind to detect eac3 files correclty at all, using the
dolby test sample 'eac3sample12.eac3' from dolby conformance test suite as
an example (I can probably upload this somewhere once i check its ok to do
so), it reports the file as:

/GstPipeline:pipeline0/GstTypeFindElement:typefindelement0.GstPad:src: caps
= video/mpeg, systemstream=(boolean)false, mpegversion=(int)4,

If I try to demux the file with qtdemux it fails, so i don't think the file
is in an MPEG container, MediaInfo just shows it as an E-A3 file.

This is with version 0.10.x


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