[FFmpeg-devel] [PATCH 4/5] binkaudio: simplify frame_len_bits and frame_len calculation

[Kostya]

On Sun, Feb 20, 2011 at 12:24:48PM +1100, Peter Ross wrote:
> ---
>  libavcodec/binkaudio.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/libavcodec/binkaudio.c b/libavcodec/binkaudio.c
> index b601a01..116bf5b 100644
> --- a/libavcodec/binkaudio.c
> +++ b/libavcodec/binkaudio.c
> @@ -81,7 +81,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
>      } else {
>          frame_len_bits = 11;
>      }
> -    s->frame_len = 1 << frame_len_bits;
>  
>      if (avctx->channels > MAX_CHANNELS) {
>          av_log(avctx, AV_LOG_ERROR, "too many channels: %d\n", avctx->channels);
> @@ -91,14 +90,13 @@ static av_cold int decode_init(AVCodecContext *avctx)
>      if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) {
>          // audio is already interleaved for the RDFT format variant
>          sample_rate  *= avctx->channels;
> -        s->frame_len *= avctx->channels;
>          s->channels = 1;
> -        if (avctx->channels == 2)
> -            frame_len_bits++;
> +        frame_len_bits += av_log2(avctx->channels);
>      } else {
>          s->channels = avctx->channels;
>      }
>  
> +    s->frame_len     = 1 << frame_len_bits;
>      s->overlap_len   = s->frame_len / 16;
>      s->block_size    = (s->frame_len - s->overlap_len) * s->channels;
>      sample_rate_half = (sample_rate + 1) / 2;
> -- 
> 1.7.1

How many channels are possible there?
If just mono/stereo then ok, for non-power-of-two it may be just differently
wrong.