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lavf: extend / improve the AVFormatContext doxy

This commit is contained in:
Anton Khirnov 2014-02-04 18:11:40 +01:00
parent 54f7e79d47
commit 18c896be3d
1 changed files with 69 additions and 32 deletions
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101
libavformat/avformat.h
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@ -860,32 +860,41 @@ typedef struct AVFormatInternal AVFormatInternal;
*/
typedef struct AVFormatContext {
/**
* A class for logging and AVOptions. Set by avformat_alloc_context().
* A class for logging and @ref avoptions. Set by avformat_alloc_context().
* Exports (de)muxer private options if they exist.
*/
const AVClass *av_class;
/**
* Can only be iformat or oformat, not both at the same time.
* The input container format.
*
* decoding: set by avformat_open_input().
* encoding: set by the user.
* Demuxing only, set by avformat_open_input().
*/
struct AVInputFormat *iformat;
/**
* The output container format.
*
* Muxing only, must be set by the caller before avformat_write_header().
*/
struct AVOutputFormat *oformat;
/**
* Format private data. This is an AVOptions-enabled struct
* if and only if iformat/oformat.priv_class is not NULL.
*
* - muxing: set by avformat_write_header()
* - demuxing: set by avformat_open_input()
*/
void *priv_data;
/**
* I/O context.
*
* decoding: either set by the user before avformat_open_input() (then
* the user must close it manually) or set by avformat_open_input().
* encoding: set by the user.
* - demuxing: either set by the user before avformat_open_input() (then
* the user must close it manually) or set by avformat_open_input().
* - muxing: set by the user before avformat_write_header(). The caller must
* take care of closing / freeing the IO context.
*
* Do NOT set this field if AVFMT_NOFILE flag is set in
* iformat/oformat.flags. In such a case, the (de)muxer will handle
@ -896,37 +905,54 @@ typedef struct AVFormatContext {
/* stream info */
int ctx_flags; /**< Format-specific flags, see AVFMTCTX_xx */
/**
* Number of elements in AVFormatContext.streams.
*
* Set by avformat_new_stream(), must not be modified by any other code.
*/
unsigned int nb_streams;
/**
* A list of all streams in the file. New streams are created with
* avformat_new_stream().
*
* decoding: streams are created by libavformat in avformat_open_input().
* If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
* appear in av_read_frame().
* encoding: streams are created by the user before avformat_write_header().
* - demuxing: streams are created by libavformat in avformat_open_input().
* If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
* appear in av_read_frame().
* - muxing: streams are created by the user before avformat_write_header().
*
* Freed by libavformat in avformat_free_context().
*/
unsigned int nb_streams;
AVStream **streams;
char filename[1024]; /**< input or output filename */
/**
* input or output filename
*
* - demuxing: set by avformat_open_input()
* - muxing: may be set by the caller before avformat_write_header()
*/
char filename[1024];
/**
* Decoding: position of the first frame of the component, in
* Position of the first frame of the component, in
* AV_TIME_BASE fractional seconds. NEVER set this value directly:
* It is deduced from the AVStream values.
*
* Demuxing only, set by libavformat.
*/
int64_t start_time;
/**
* Decoding: duration of the stream, in AV_TIME_BASE fractional
* Duration of the stream, in AV_TIME_BASE fractional
* seconds. Only set this value if you know none of the individual stream
* durations and also do not set any of them. This is deduced from the
* AVStream values if not set.
*
* Demuxing only, set by libavformat.
*/
int64_t duration;
/**
* Decoding: total stream bitrate in bit/s, 0 if not
* Total stream bitrate in bit/s, 0 if not
* available. Never set it directly if the file_size and the
* duration are known as Libav can compute it automatically.
*/
@ -948,13 +974,16 @@ typedef struct AVFormatContext {
#define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
/**
* decoding: size of data to probe; encoding: unused.
* Maximum size of the data read from input for determining
* the input container format.
* Demuxing only, set by the caller before avformat_open_input().
*/
unsigned int probesize;
/**
* decoding: maximum time (in AV_TIME_BASE units) during which the input should
* be analyzed in avformat_find_stream_info().
* Maximum duration (in AV_TIME_BASE units) of the data read
* from input in avformat_find_stream_info().
* Demuxing only, set by the caller before avformat_find_stream_info().
*/
int max_analyze_duration;
@ -989,8 +1018,8 @@ typedef struct AVFormatContext {
* accurate seeking (depends on demuxer).
* Demuxers for which a full in-memory index is mandatory will ignore
* this.
* muxing : unused
* demuxing: set by user
* - muxing: unused
* - demuxing: set by user
*/
unsigned int max_index_size;
@ -1008,41 +1037,49 @@ typedef struct AVFormatContext {
* in the trailer. To write chapters in the trailer, nb_chapters
* must be zero when write_header is called and non-zero when
* write_trailer is called.
* muxing : set by user
* demuxing: set by libavformat
* - muxing: set by user
* - demuxing: set by libavformat
*/
unsigned int nb_chapters;
AVChapter **chapters;
/**
* Metadata that applies to the whole file.
*
* - demuxing: set by libavformat in avformat_open_input()
* - muxing: may be set by the caller before avformat_write_header()
*
* Freed by libavformat in avformat_free_context().
*/
AVDictionary *metadata;
/**
* Start time of the stream in real world time, in microseconds
* since the unix epoch (00:00 1st January 1970). That is, pts=0
* in the stream was captured at this real world time.
* - encoding: Set by user.
* - decoding: Unused.
* since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
* stream was captured at this real world time.
* Muxing only, set by the caller before avformat_write_header().
*/
int64_t start_time_realtime;
/**
* decoding: number of frames used to probe fps
* The number of frames used for determining the framerate in
* avformat_find_stream_info().
* Demuxing only, set by the caller before avformat_find_stream_info().
*/
int fps_probe_size;
/**
* Error recognition; higher values will detect more errors but may
* misdetect some more or less valid parts as errors.
* - encoding: unused
* - decoding: Set by user.
* Demuxing only, set by the caller before avformat_open_input().
*/
int error_recognition;
/**
* Custom interrupt callbacks for the I/O layer.
*
* decoding: set by the user before avformat_open_input().
* encoding: set by the user before avformat_write_header()
* demuxing: set by the user before avformat_open_input().
* muxing: set by the user before avformat_write_header()
* (mainly useful for AVFMT_NOFILE formats). The callback
* should also be passed to avio_open2() if it's used to
* open the file.