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/*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVFILTER_FORMATS_H
#define AVFILTER_FORMATS_H
#include "avfilter.h"
/**
* A list of supported formats for one end of a filter link. This is used
* during the format negotiation process to try to pick the best format to
* use to minimize the number of necessary conversions. Each filter gives a
* list of the formats supported by each input and output pad. The list
* given for each pad need not be distinct - they may be references to the
* same list of formats, as is often the case when a filter supports multiple
* formats, but will always output the same format as it is given in input.
*
* In this way, a list of possible input formats and a list of possible
* output formats are associated with each link. When a set of formats is
* negotiated over a link, the input and output lists are merged to form a
* new list containing only the common elements of each list. In the case
* that there were no common elements, a format conversion is necessary.
* Otherwise, the lists are merged, and all other links which reference
* either of the format lists involved in the merge are also affected.
*
* For example, consider the filter chain:
* filter (a) --> (b) filter (b) --> (c) filter
*
* where the letters in parenthesis indicate a list of formats supported on
* the input or output of the link. Suppose the lists are as follows:
* (a) = {A, B}
* (b) = {A, B, C}
* (c) = {B, C}
*
* First, the first link's lists are merged, yielding:
* filter (a) --> (a) filter (a) --> (c) filter
*
* Notice that format list (b) now refers to the same list as filter list (a).
* Next, the lists for the second link are merged, yielding:
* filter (a) --> (a) filter (a) --> (a) filter
*
* where (a) = {B}.
*
* Unfortunately, when the format lists at the two ends of a link are merged,
* we must ensure that all links which reference either pre-merge format list
* get updated as well. Therefore, we have the format list structure store a
* pointer to each of the pointers to itself.
*/
struct AVFilterFormats {
unsigned nb_formats; ///< number of formats
int *formats; ///< list of media formats
unsigned refcount; ///< number of references to this list
struct AVFilterFormats ***refs; ///< references to this list
};
typedef struct AVFilterChannelLayouts {
uint64_t *channel_layouts; ///< list of channel layouts
int nb_channel_layouts; ///< number of channel layouts
unsigned refcount; ///< number of references to this list
struct AVFilterChannelLayouts ***refs; ///< references to this list
} AVFilterChannelLayouts;
/**
* Return a channel layouts/samplerates list which contains the intersection of
* the layouts/samplerates of a and b. Also, all the references of a, all the
* references of b, and a and b themselves will be deallocated.
*
* If a and b do not share any common elements, neither is modified, and NULL
* is returned.
*/
AVFilterChannelLayouts *ff_merge_channel_layouts(AVFilterChannelLayouts *a,
AVFilterChannelLayouts *b);
AVFilterFormats *ff_merge_samplerates(AVFilterFormats *a,
AVFilterFormats *b);
/**
* Construct an empty AVFilterChannelLayouts/AVFilterFormats struct --
* representing any channel layout/sample rate.
*/
AVFilterChannelLayouts *ff_all_channel_layouts(void);
AVFilterFormats *ff_all_samplerates(void);
/**
* A helper for query_formats() which sets all links to the same list of channel
* layouts/sample rates. If there are no links hooked to this filter, the list
* is freed.
*/
void ff_set_common_channel_layouts(AVFilterContext *ctx,
AVFilterChannelLayouts *layouts);
void ff_set_common_samplerates(AVFilterContext *ctx,
AVFilterFormats *samplerates);
/**
* A helper for query_formats() which sets all links to the same list of
* formats. If there are no links hooked to this filter, the list of formats is
* freed.
*/
void ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout);
/**
* Add *ref as a new reference to f.
*/
void ff_channel_layouts_ref(AVFilterChannelLayouts *f,
AVFilterChannelLayouts **ref);
/**
* Remove a reference to a channel layouts list.
*/
void ff_channel_layouts_unref(AVFilterChannelLayouts **ref);
void ff_channel_layouts_changeref(AVFilterChannelLayouts **oldref,
AVFilterChannelLayouts **newref);
int ff_default_query_formats(AVFilterContext *ctx);
/**
* Create a list of supported formats. This is intended for use in
* AVFilter->query_formats().
*
* @param fmts list of media formats, terminated by -1
* @return the format list, with no existing references
*/
AVFilterFormats *ff_make_format_list(const int *fmts);
/**
* Add fmt to the list of media formats contained in *avff.
* If *avff is NULL the function allocates the filter formats struct
* and puts its pointer in *avff.
*
* @return a non negative value in case of success, or a negative
* value corresponding to an AVERROR code in case of error
*/
int ff_add_format(AVFilterFormats **avff, int fmt);
/**
* Return a list of all formats supported by Libav for the given media type.
*/
AVFilterFormats *ff_all_formats(enum AVMediaType type);
/**
* Construct a formats list containing all planar sample formats.
*/
AVFilterFormats *ff_planar_sample_fmts(void);
/**
* Return a format list which contains the intersection of the formats of
* a and b. Also, all the references of a, all the references of b, and
* a and b themselves will be deallocated.
*
* If a and b do not share any common formats, neither is modified, and NULL
* is returned.
*/
AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
/**
* Add *ref as a new reference to formats.
* That is the pointers will point like in the ascii art below:
* ________
* |formats |<--------.
* | ____ | ____|___________________
* | |refs| | | __|_
* | |* * | | | | | | AVFilterLink
* | |* *--------->|*ref|
* | |____| | | |____|
* |________| |________________________
*/
void ff_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
/**
* If *ref is non-NULL, remove *ref as a reference to the format list
* it currently points to, deallocates that list if this was the last
* reference, and sets *ref to NULL.
*
* Before After
* ________ ________ NULL
* |formats |<--------. |formats | ^
* | ____ | ____|________________ | ____ | ____|________________
* | |refs| | | __|_ | |refs| | | __|_
* | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
* | |* *--------->|*ref| | |* | | | |*ref|
* | |____| | | |____| | |____| | | |____|
* |________| |_____________________ |________| |_____________________
*/
void ff_formats_unref(AVFilterFormats **ref);
/**
*
* Before After
* ________ ________
* |formats |<---------. |formats |<---------.
* | ____ | ___|___ | ____ | ___|___
* | |refs| | | | | | |refs| | | | | NULL
* | |* *--------->|*oldref| | |* *--------->|*newref| ^
* | |* * | | |_______| | |* * | | |_______| ___|___
* | |____| | | |____| | | | |
* |________| |________| |*oldref|
* |_______|
*/
void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref);
#endif /* AVFILTER_FORMATS_H */
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