[FFmpeg-devel] [PATCH] Add a new channel layout API

[Michael Niedermayer]

On Mon, Oct 28, 2019 at 02:48:21PM +0100, Paul B Mahol wrote:
> The new API is more extensible and allows for custom layouts.
> More accurate information is exported, eg for decoders that do not
> set a channel layout, lavc will not make one up for them.
> 
> Deprecate the old API working with just uint64_t bitmasks.
> 
> Original commit by Anton Khirnov <anton at khirnov.net>.
> Expanded and completed by Vittorio Giovara <vittorio.giovara at gmail.com>.
> Adapted for FFmpeg by Paul B Mahol <onemda at gmail.com>.
> 
> Signed-off-by: Anton Khirnov <anton at khirnov.net>
> Signed-off-by: Vittorio Giovara <vittorio.giovara at gmail.com>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavutil/channel_layout.c | 385 ++++++++++++++++++++++++++++------
>  libavutil/channel_layout.h | 411 ++++++++++++++++++++++++++++++++++---
>  libavutil/version.h        |   3 +
>  3 files changed, 709 insertions(+), 90 deletions(-)
> 
> diff --git a/libavutil/channel_layout.c b/libavutil/channel_layout.c
> index 3bd5ee29b7..9112af32a6 100644
> --- a/libavutil/channel_layout.c
> +++ b/libavutil/channel_layout.c
[...]

./ffmpeg  -v 0 -layouts
looses the channel names 



[...]
> +void av_channel_layout_from_mask(AVChannelLayout *channel_layout,
> +                                 uint64_t mask)
> +{
> +    channel_layout->order       = AV_CHANNEL_ORDER_NATIVE;
> +    channel_layout->nb_channels = av_popcount64(mask);

is this correct in relation to AV_CH_LAYOUT_NATIVE ?


> +    channel_layout->u.mask      = mask;
> +}


[...]
> +/**
> + * Initialize a native channel layout from a bitmask indicating which channels
> + * are present.
> + *
> + * @note channel_layout should be properly allocated as described above.
> + *
> + * @param channel_layout the layout structure to be initialized
> + * @param mask bitmask describing the channel layout
> + */
> +void av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);

This possibly should return a error code
for example a mask of 0 would not be valid

thx

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

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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