[FFmpeg-devel] [PATCH] swresample: Use channel count in rematrix initialization

[Michael Niedermayer]

On Sat, Jul 21, 2018 at 07:31:12PM +0100, Marcin Gorzel wrote:
> Rematrixing supports up to 64 channels. However, there is only a limited number of channel layouts defined. Since the in/out channel count is currently obtained from the channel layout, for undefined layouts (e.g. for 9, 10, 11 channels etc.) the rematrixing fails.
> 
> This patch changes rematrix init methods to use in/out channel count directly instead of computing it from channel layout.
> ---
>  libswresample/rematrix.c          | 4 ++--
>  libswresample/x86/rematrix_init.c | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/libswresample/rematrix.c b/libswresample/rematrix.c
> index 8227730056..ec1909dc0c 100644
> --- a/libswresample/rematrix.c
> +++ b/libswresample/rematrix.c
> @@ -384,8 +384,8 @@ av_cold static int auto_matrix(SwrContext *s)
>  
>  av_cold int swri_rematrix_init(SwrContext *s){
>      int i, j;
> -    int nb_in  = av_get_channel_layout_nb_channels(s->in_ch_layout);
> -    int nb_out = av_get_channel_layout_nb_channels(s->out_ch_layout);
> +    int nb_in = s->in.ch_count;
> +    int nb_out = s->out.ch_count;
>  
>      s->mix_any_f = NULL;

This is much better than the previous patch
still, why is this not using used_ch_count ?

Lets look at the code in swresample.c, as i dont remember 100% ...
First stage is in_convert, its initialized with:
s->in_convert = swri_audio_convert_alloc(s->int_sample_fmt,
                                             s-> in_sample_fmt, s->used_ch_count, s->channel_map, 0);

You can see here that used_ch_count is its output 
and next stages are resample and rematrix (in either order)

how can they have s->in.ch_count as input ?

and yes, it seems there is no testcase that catches this, which is
unfortunate.

a much more minor issue is, please vertically align the "=" as it was
before the patch.

Thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
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