[FFmpeg-devel] ALS optimizations
Fri Dec 17 08:25:50 CET 2010
On Thu, 16 Dec 2010, Justin Ruggles wrote:
> On 12/16/2010 08:56 AM, Guennadi Liakhovetski wrote:
> > I'm trying to optimize ALS decoding for a specific platform. There are
> > several repeated MUL64() calls in libavcodec/alsdec.c, that can be very
> > well optimized. one of them already provided a 10% boost. But others lie
> > on paths, that are never entered with sample ALS files from "fate." How
> > can I produce or where can I get from files, that would also use those
> > other paths?
> > E.g., in decode_var_block_data() "if (*bd->use_ltp)" is never entered,
> > similarly "if (bd->ra_block)" and revert_channel_correlation() is never
> > called at all.
> The files in FATE do not cover all features of ALS (there are many
> features). There are more reference files available from ISO or you can
> create your own that use various features using the reference encoder.
I have been also pointed out to the reference software from TU-Berlin,
which I've downloaded and used to create a couple of files, which a recent
ffmpeg couldn't decode - even without any options. As for available ISO
files - couldn't find any, are they not only for members / for a fee?
Would you happen to have a link at hand?
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
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