FFMPEG SDK软硬解码基础-CFANZ编程社区

都有啥

解封装
软硬件解码
像素格式转换
重采样
pts/dts
同步策略

FFMPEG解封装

总览

av_register_all()
avformat_network_init()
avformat_open_input(...)
avformat_find_stream_info(...)
av_find_best_stream(...)
AVFormatContext AVStream AVPacket
av_read_frame(...)

avformat_open_input

确保av_register_all avformat_network_init已调用
AVFormatContext **ps
const char *url
AVInputFormat *fmt
AVDictionary **options

AVFormatContext

AVIOContext *pb; char filename[1024];
unsigned int nb_streams;
AVStream **streams;
int64_6 duration; //AV_TIME_BASE
int64_t bit_rate
void avformat-close_input(AVFormatContext **s);

avformat_find_stream_info

int avformat_find_stream_info(
AVFormatContext *ic,
AVDictionary **options
);
flv(没法获取时长) h264 mpeg2

AVStream

AVCodecContext *codec; //过时了
AVRational time_base;
int64_t duration;
int64_t nb_frames;
AVRational avg_frame_rate;
AVCodecParameters *codecpar;(音视频参数)

AVCodecParameters

enum AVMediaType codec_type;
enum AVCodecID codec_id;
uint32_t codec_tag
int format
int width; int height;
uint64_t channel_layout; int channels; int sample_rate; int frame_size;

static double r2d(AVRational r)
{	
	return r.num==0||r.den==0?0:(double)r.num/(double)r.den;
}

av_find_best_stream

int av_find_best_stream(
AVFormatContext * ic,
enum AVMediaType type,
int wanted_stream_nb,
int related_stream,
AVCodec** decoder_ret,
int flags
)

av_read_frame

AVFormatContext *s
AVPacket *pkt
return 0 if OK, < 0 on error or end of file

AVPacket

AVBufferRef *bug
int64_t pts; // pts * (num/den)
int64_t dts;
uint8_t data; int size;
AVPacket *av_packet_alloc(void);创建并初始化
AVPacket *av_packet_clone(const AVPacket *src); 创建并并用计数
int av_packet_ref(AVPacket *dst, const AVpacket *src); av_packet_unref(AVPacket *pkt)
void av_packet_free(AVPacket ** pkt); 清空对象并减引用计数
void av_init_packet(AVPacket *pkt);默认值
int av_packet_from_data(AVPacket *pkt, uint8_t *data, int size);
int av_copy_packet(AVPacket *dst, const AVPacket *src); attribute_deprecated

av_seek_frame

int av_seek_frame(AVFormatContext *s, int stream_index, // -1 default
int 64_t timestampe, //AVStream.time_base
int flags);

av_seek_frame flag

#define AVSEEK_FLAG_BACKWARD 1 /// < seek backward
#define AVSEEK_FLAG_BYTE 2 /// < seeking based on position in bytes
#define AVSEEK_FLAG_ANY 3 /// < seeking to any frame, even non-keyframes
#define AVSEEK_FLAG_FRAME 4 /// < seeking based on frame number

软硬件解码

avcodec_find_decoder

avcodec_register_all();
AVCodec *avcodec_find_decoder(enum AVCodecID id);
AVCodec *avcodec_find_decoder_by_name(const char *name);
avcodec_find_decoder_by_name(“h264_mediacodec”);

AVCodecContext

AVCodecContext *avcodec_alloc_context3(const AVCodec * codec)
void avcodec_free_context(AVCodecContext **avctx);
int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
/libavcodec/options_table.h
int thread_count;
time_base

avcodec_parameters_to_context

avcodec_parameters_to_context(codec, p);

AVFrame

AVFrame *frame = av_frame_alloc();
void av_frame_free(AVFrame **frame);
int av_frame_ref(AVFrame *dst, const AVFrame *src);
AVFrame *av_frame_clone(const AVFrame *src);
void av_frame_unref(AVFrame *frame);
uint8_t *data[AV_NUM_DATA_POINTERS];
int linesize[AV_NUM_DATA_POINTERS];
int width, height; int nb_samples;
int64_t pts; int64_t pkt_dts;
int sample_rate; uint64_t channel_layout; int. channels;
int format; //AVPixelFormat AVSampleFormat

linesize

FFMPEG SDK软硬解码基础_音视频

FFMPEG SDK软硬解码基础_android_02

FFMPEG SDK软硬解码基础_#define_03

avcodec_send_packet

int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);

avcodec_receive_frame

int avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame);

重采样和像素格式转换

视频像素和是和尺寸转换

sws_getContext
struct SwsContext *sws_getCachedContext( struct SwsContext *context,
							int srcW, int srcH, enum AVPixelFormat srcFormat,
							int dstW, int dstH, enum AVPixelFormat dstFormat,
							int flags, SwsFilter *srcFilter,
							SwsFilter *dstFilter, const double *param);

int sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[],
		const int srcStride[], int srcSliceY, int srcSliceH,
		uint8_t *const dst[], const int dstStride[]);
void sws_freeContext(struct SwsContext *swsContext);

#define SWS_FAST_BILINEAR 1
#define SWS_BILINEAR 2
#define SWS_BICUBIC 4
#define SWS_X 8
#define SWS_POINT 0x10
#define SWS_AREA 0x20
#define SWS_BICUBLIN 0x40

SwrContext

SwrContext *swr_alloc(void);
SwrContext *swr_alloc_set_opts(
	struct SwrContext *s, int64_t out_ch_layout,
	AVSampleFormat out_sample_fmt, int out_sample_rate,
	int64_t in_ch_layout, AVSampleFormat in_sample_fmt, int in_sample_rate,
	ing log_offset, void *log_ctx);
)
int swr_init(struct SwrContext *s);
void swr_free(struct SwrContext **s);

swr_convert

inv swr_convert(struct SwrContext *s, uint8_t **out, int out_count, const uint8_t **in, int in_count);

NDK绘制SurfaceView 3-1

cmake android
#include <android/native_window.h>
Einclude <android/native_window_jni.h>

NDK绘制SurfaceView3-2

ANativeWindow *nativeWindow = ANativveWindow_fromSurface(env, surface);
// 设置native window的buffer大小，可自动拉伸
ANativeWindow_setBuffersGeometry(natie Window, width, height, WINDOW_FORMAT_RGBA_8888);

NDK绘制SurfaceView3-3

ANativeWindow_Buffer windowBuffer;
ANativeWndow_lock(nativeWindow, &windowBuffer, 0);
uint8_t *dst = (uint8_t *)windowBuffer.bits;
memcpy(dst, rgb, widthheight4);
ANativeWindow_unlockAndPost(nativeWindow);

OpenSL ES

FFMPEG SDK软硬解码基础_封装_04

FFMPEG SDK软硬解码基础_#define_05

初始化引擎

//引擎接口
SLObjectltf engineObject = NULL;
SLEngineItf engineEngine = NULL;
slCreateEngine(&engineObject, 0, NULL, 0, NULL, NULL);
(*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
(*engineObject)->GetInterface(engineObjet, SL_IID_ENGINE, &engineEngline);

slCreateEngine

SL_AP SLresult SLAPINENTRY slCreateEngine(
SLObject ltf *pEngine,
SLuint32 numOptions
const SLEngineOption * pEngineOptions, //选择项目默认参数
SLuint32 numInterfaces,
const SLInterfaceID *pInterfaceIds, //支持的接口
const SLboolean * pInterfaceRequired // 接口标识数值，是否支持
)

SLObjectltf

SLresult(*Realize) (
SLObjectltf self,
SLboolean async
)
对象已实现状态（false阻塞）
If SL_BOOLEAN_FALSE, the method will block until termination. Otherwise, the method will return SL_RESULT_SUCCESS, and will be executed asnychronously.

GetInterface

SLresult(* GetInterface)(
SLObjectltf self,
const SLInterfaceId iid,
void * pInterface
)

创建输出设备

SLEnginelft engineEngine = NULL;
SLObjectltf outputMixObject = NULL;
(*engineEngine)->CreateOutpuMix(engineEngine, &outputMixObject, 0, 0, 0);
(*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
SLDataLocator_OutputMix outputMix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};
SLDataSink audioSnk = {&outputMix, NULL};

配置PCM格式信息

SLDataLocator_AndroidSimpleBufferQueue
android_queue={SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 2};
SLDataFormat_PCM pcm={
SL_DATAFORMAT_PCM, //播放pcm格式的数据
2, //2个声道（立体声）
SL_SAMPLINGRATE_44_1, //44100hz的频率
SL_PCMSAMPLEFORMAT_FIXED_16, //位数16位
SL_PCMSAMPLEFORMAT_FIXED_16, //和位数一致就行
SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, //立体声（前左后右）
SL_BYTEORDER_LITTLEENDIAN //结束标志
}
SLDataSource slDataSource = {&android_queue, &pcm};

初始化播放器

const SLInterfaceID ids[1] = {SL_IID_BUFFERQUEUE};
const SLboolean req[1] = {SL_BOOLEAN_TRUE};
(*engineEngine)->CreateAudioPlayer(engineEngine, &pcmPlayerObject, &slDataSource, &audioSnk, 1, ids, req);
// 初始化播放器
(*pcmPlayerObject)->Realize(pcmPlayerObject, SL_BOOLEAN_FALSE);
// 得到接口后调用获取Player接口
(*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_PLAY, pcmPlayerPlay);

播放和缓冲队列

注册回调缓冲区获取缓冲队列接口（*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_BUFFERQUEUE, &pcmBufferQueue);
(*pcmBufferQueue)->RegisterCallback(pcmBufferQueue, pcmBufferCallBack, NULL);
(*pcmPlayerPlay)->SetPlayState(pcmPlayerPlay, SL_PLAYSTATE_PLAYING);
(*pcmBufferQueue)->Enqueue(pcmBufferQueue, “”, 1);