[vlc-devel] [PATCH 2/2] avcodec: do not reorder Ambisonics channels encoded in AAC

[Francois Cartegnie]

Le 21/12/2017 à 18:18, Adrien Maglo a écrit :
> Keep the codec order to achieve a correct Ambisonics rendering.
> ---
>  modules/codec/avcodec/audio.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/modules/codec/avcodec/audio.c b/modules/codec/avcodec/audio.c
> index 6b43627c1e..b9eb7d5856 100644
> --- a/modules/codec/avcodec/audio.c
> +++ b/modules/codec/avcodec/audio.c
> @@ -624,6 +624,20 @@ static void SetupOutputFormat( decoder_t *p_dec, bool b_trust )
>          if( i_channels_dst != i_channels_src && b_trust )
>              msg_Warn( p_dec, "%d channels are dropped", i_channels_src - i_channels_dst );
>  
> +        /* Restore the right order of Ambisonic order 1 channels encoded in AAC... */
> +        if (p_dec->fmt_out.audio.channel_type == AUDIO_CHANNEL_TYPE_AMBISONICS
> +            && p_dec->fmt_in.i_codec == VLC_CODEC_MP4A
> +            && i_channels_src == 4)
> +        {
> +            p_sys->pi_extraction[0] = 2;
> +            p_sys->pi_extraction[1] = 0;
> +            p_sys->pi_extraction[2] = 1;
> +            p_sys->pi_extraction[3] = 3;
> +            i_layout_dst = AOUT_CHAN_CENTER | AOUT_CHAN_LEFT
> +                    | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER;
> +            p_sys->b_extract = true;
> +        }
> +
>          p_dec->fmt_out.audio.i_physical_channels = i_layout_dst;
>      }
>      else
> 

Only you can tell

-- 
Francois Cartegnie
VideoLAN - VLC Developer