Files
Video-Editing-Automation/include/VideoContext.h
2019-03-05 00:05:27 -05:00

144 lines
3.9 KiB
C

/**
* @file VideoContext.h
* @author Devon Crawford
* @date February 21, 2019
* @brief File containing the definition and usage for VideoContext API:
* The primary data structure for raw media files, videos just as they
* are on disk.
* Higher level structures such as Clip build ontop of this.
*/
#ifndef _VIDEOCONTEXT_API_
#define _VIDEOCONTEXT_API_
#include <stdio.h>
#include <libavformat/avformat.h>
#include <libavutil/pixdesc.h>
#include <stdbool.h>
#include <sys/stat.h>
enum PacketStreamType { DEC_STREAM_NONE = -1, DEC_STREAM_VIDEO, DEC_STREAM_AUDIO };
typedef struct VideoContext {
/*
Open file information
*/
AVFormatContext *fmt_ctx; // fmt_ctx->streams[stream_index] contains all streams
/*
Codecs used for decoding.
Encoding is handled by OutputContext, since the entire sequence
needs to be encoded with the same codec and codec parameters
*/
AVCodec *video_codec, *audio_codec;
/*
CodecContexts used for demuxing
*/
AVCodecContext *video_codec_ctx, *audio_codec_ctx;
/*
index of stream in fmt_ctx->streams[stream_index]
*/
int video_stream_idx, audio_stream_idx;
/*
internal use only. used in clip_read_frame()
*/
enum PacketStreamType last_decoder_packet_stream;
/*
video context open or closed state
*/
bool open;
/*
File stats such as creation time.
"sb.st_mtime" is what we want.
This will show the last modified date of the file (creation time).
*/
struct stat file_stats;
/*
filename
*/
char *url;
/*
Timebases fetched when the file is first opened.
After the file is open, get timebase from here to avoid opening the file again
*/
AVRational video_time_base, audio_time_base;
/*
frames per second of original video
*/
double fps;
/*
pts of seek, absolute to original video pts.
time_base is the same as VideoContext video_stream time_base
RANGE:
>= orig_start_pts and < orig_end_pts of Clip.
*/
int64_t seek_pts;
/*
By default this is start_frame_pts, but will change when reading packets.
(We track this by video packets seen and seek usage)
*/
int64_t curr_pts;
/*
number of clips associated with this VideoContext.
We must only free a VideoContext when the last clip using it is freed
*/
int clip_count;
} VideoContext;
# define VIDEO_CONTEXT_STREAM_TYPES_LEN 2
AVStream *get_video_stream(VideoContext *vid_ctx);
AVStream *get_audio_stream(VideoContext *vid_ctx);
AVRational get_video_time_base(VideoContext *vid_ctx);
AVRational get_audio_time_base(VideoContext *vid_ctx);
/*
out @param vid_ctx - allocated context containing format, streams and codecs
in @param filename - name of video file
Return >= 0 if OK, < 0 on fail
*/
int open_video_context(VideoContext *vid_ctx, char *filename);
/* Return >=0 if OK, < 0 on fail */
int open_format_context(VideoContext *vid_ctx, char *filename);
/**
Finds a stream and its associated codec
Call this function after open_format_context() - for each AVMediaType
Returns >= 0 if OK, < 0 on fail
*/
int open_codec_context(VideoContext *vid_ctx, enum AVMediaType type);
void init_video_context(VideoContext *vid_ctx);
/** free codecs and ffmpeg struct data inside VideoContext **/
void close_video_context(VideoContext *vid_ctx);
/**
* Free all videoContext data (including url)
* @param vid_ctx VideoContext
*/
void free_video_context(VideoContext **vc);
/**
* Check if AVRational is valid
* @param r AVRational to check
* @return true if invalid
*/
bool valid_rational(AVRational r);
/**
* Print most data within an AVCodecContext
* @param c AVCodecContext with data
* @return char * allocated on heap, it is the callers responsibility to free
*/
char *print_codec_context(AVCodecContext *c);
#endif