Quoting Mark Thompson (2016-02-20 19:30:14)
> ---
> libavutil/hwcontext.c | 38 +++++++++++++++++++++++++++
> libavutil/hwcontext.h | 58
> ++++++++++++++++++++++++++++++++++++++++++
> libavutil/hwcontext_internal.h | 10 ++++++++
> 3 files changed, 106 insertions(+)
>
> diff --git a/libavutil/hwcontext.c b/libavutil/hwcontext.c
> index b6d0518..b193212 100644
> --- a/libavutil/hwcontext.c
> +++ b/libavutil/hwcontext.c
> @@ -400,3 +400,41 @@ int av_hwframe_get_buffer(AVBufferRef *hwframe_ref,
> AVFrame *frame, int flags)
>
> return 0;
> }
> +
> +AVHWFramesConstraints *av_hwframe_constraints_alloc(void)
> +{
> + AVHWFramesConstraints *constraints;
> +
> + constraints = av_mallocz(sizeof(*constraints));
> + if (!constraints)
> + return NULL;
> +
> + constraints->min_width = constraints->min_height = 0;
> + constraints->max_width = constraints->max_height = INT_MAX;
> +
> + return constraints;
> +}
> +
> +void *av_hwdevice_hwconfig_alloc(AVBufferRef *ref)
> +{
> + AVHWDeviceContext *ctx = (AVHWDeviceContext*)ref->data;
> + const HWContextType *hw_type = ctx->internal->hw_type;
> +
> + if (hw_type->device_hwconfig_size == 0)
> + return NULL;
> +
> + return av_mallocz(hw_type->device_hwconfig_size);
> +}
> +
> +int av_hwdevice_get_hwframe_constraints(AVBufferRef *ref,
> + void *hwconfig,
> + AVHWFramesConstraints *constraints)
> +{
> + AVHWDeviceContext *ctx = (AVHWDeviceContext*)ref->data;
> + const HWContextType *hw_type = ctx->internal->hw_type;
> +
> + if (!hw_type->frames_get_constraints)
> + return AVERROR(ENOSYS);
> +
> + return hw_type->frames_get_constraints(ctx, hwconfig, constraints);
> +}
> diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
> index 81ae817..a73c515 100644
> --- a/libavutil/hwcontext.h
> +++ b/libavutil/hwcontext.h
> @@ -326,4 +326,62 @@ int av_hwframe_transfer_get_formats(AVBufferRef
> *hwframe_ctx,
> enum AVPixelFormat **formats, int flags);
>
>
> +/**
> + * This struct describes the constraints on hardware frames attached to
> + * a given device with a hardware-specific configuration.
> + */
> +typedef struct AVHWFramesConstraints {
> + /**
> + * A list of possible values for sw_format in the hw_frames_ctx.
> + * The list is terminated by AV_PIX_FMT_NONE and must be freed by the
> + * caller with av_free() when the whole constraint structure is freed.
> + * Can be NULL if this information is not known.
> + */
> + enum AVPixelFormat *valid_sw_formats;
I think it would be better to add a destructor for AVHWFramesConstraints
and free this array there.
Otherwise, if we add more allocated fields to it, old callers won't
free them, resulting in memleaks.
> +
> + /**
> + * The minimum size of frames in this hw_frames_ctx.
> + * (Zero if not known.)
> + */
> + int min_width;
> + int min_height;
> +
> + /**
> + * The maximum size of frames in this hw_frames_ctx.
> + * (INT_MAX if not known / no limit.)
> + */
> + int max_width;
> + int max_height;
> +} AVHWFramesConstraints;
> +
> +/**
> + * Allocate an AVHWFrameConstraints structure for a given hwdevice.
> + *
> + * @return The newly created AVHWFrameConstraints structure.
> + */
> +AVHWFramesConstraints *av_hwframe_constraints_alloc(void);
> +
> +/**
> + * Allocate a HW-specific configuration structure for a given HW device.
> + *
> + * @param device_ctx a reference to the associated AVHWDeviceContext.
> + * @return The newly created HW-specific configuration structure on
> + * success or NULL on failure.
> + */
> +void *av_hwdevice_hwconfig_alloc(AVBufferRef *device_ctx);
> +
> +/**
> + * Get the constraints on HW frames given a device and the HW-specific
> + * configuration to be used with that device.
> + *
> + * @param device_ctx a reference to the associated AVHWDeviceContext.
> + * @param hwconfig a filled HW-specific configuration structure.
> + * @param constraints on successful return, the constraints which apply
> + * to frames in this device configuration.
> + * @return 0 on success, a negative AVERROR code on failure.
> + */
> +int av_hwdevice_get_hwframe_constraints(AVBufferRef *device_ctx,
> + void *hwconfig,
Should this be const? It's not completely clear from the API whether
hwconfig is read-only to this function and how it should be freed.
I guess your intention was to have it freed just by av_free() and all
fields in it are assumed to be owned by the caller at all times. That is
ok with me, but should be clearly documented.
--
Anton Khirnov
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