[FFmpeg-devel] [PATCH] ac3enc: change default floor code to 7.

[Måns Rullgård]

Justin Ruggles <justin.ruggles at gmail.com> writes:

> This is to match the value in every (E-)AC-3 file from commercial sources.
> It has a negligible effect on audio quality.
> ---
>  libavcodec/ac3enc.c        |    2 +-
>  tests/ref/acodec/ac3_fixed |    2 +-
>  tests/ref/lavf/rm          |    2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)

What is the effect of this change?  Why is matching commercial encoders
valuable?

> diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
> index 851fdc9..dc7e4ad 100644
> --- a/libavcodec/ac3enc.c
> +++ b/libavcodec/ac3enc.c
> @@ -752,7 +752,7 @@ static void bit_alloc_init(AC3EncodeContext *s)
>      s->fast_decay_code = 1;
>      s->slow_gain_code  = 1;
>      s->db_per_bit_code = 3;
> -    s->floor_code      = 4;
> +    s->floor_code      = 7;

FWIW, 4 is mentioned as a nominal default in the spec.

-- 
M?ns Rullg?rd
mans at mansr.com