[Mp4-tech] BSAC Audio Reference Code Bugs

chris dunn chris.dunn scalatech.co.uk
Thu Oct 21 22:10:08 EDT 2004


Hi All
I've been running a win32 build of the BSAC codec contained within the
MPEG 4 Reference Code, 2001 Edition, available at:
http://www.iso.ch/iso/en/ittf/PubliclyAvailableStandards/ISO_IEC_14496-5_2001_Software_Reference/audio.zip
I'd be grateful if anyone can suggest solutions to the following
problems:
1. The codec works ok for mono sources, but does not appear to operate
for stereo signals.
2. The BSAC encoder appears to operate permanently in VBR mode, with
the -vr switch having no effect, hence the decoder -r switch cannot be
used to scale encoded bitrate. Is does not seem possible to operate the
encoder in fixed bitrate mode.
3. Window switching enabled mode (-wsm 10) crashes the BSAC encoder,
hence can only operate in long block mode (-wsm 0) with resulting
prenoise artifacts for transient material.
4. The decoder rewrite will not decode BSAC bitstreams that successfully
decode with the original decoder.
Alternatively does anyone know of a more recent (and publicly available)
version of the reference software ?
Regards,
Chris Dunn
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Scala Technology Ltd
http://www.scalatech.co.uk
+44 20 7267 1604 (direct)
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