[原]如何在Android用FFmpeg+SDL2.0解码显示图像

2023-08-14 20:40:40

如何在Android上使用FFmpeg解码图像参考文章[原]如何在Android用FFmpeg解码图像，如何在Android上使用SDL2.0来显示图像参考[原]零基础学习SDL开发之在Android使用SDL2.0显示BMP图。有了以上两篇文章的基础我们就可以在Android使用FFmpeg来解码图像并且使用SDL2.0来显示输出的图像了。

博主的开发环境：Ubuntu 14.04 64位，Eclipse+CDT+ADT+NDK。

在文章开始之前假定你已经知道如何使用NDK编译FFmpeg，以及知道如何移植SDL2.0到Android平台上来了，如有不明白的可以参考文章开头的两篇文章。

工程中的目录结构：ffmpeg文件夹下是ffmpeg相关的头文件以及编译的Android makefile文件，SDL文件夹下面是SDL2.0相关的头文件以及相关的源码和编译用的Android makefile 文件，player文件下是用来解码与显示相关的代码和Android makefile。

一、参考[原]零基础学习SDL开发之在Android使用SDL2.0显示BMP图创建一个工程，创建jni文件，在jni下创建SDL文件夹，将相应的头文件以及源码拷贝过来。在这里也可以参考[原]如何在Android用FFmpeg解码图像将编译好的动态库作为PREBUILT_SHARED_LIBRARY来加载。SDL文件下的Android.mk内容：

LOCAL_PATH := $(call my-dir)

###########################

#

# SDL shared library

#

###########################

include $(CLEAR_VARS)

LOCAL_MODULE := SDL2

LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

LOCAL_EXPORT_C_INCLUDES := $(LOCAL_C_INCLUDES)

LOCAL_SRC_FILES := \

    $(subst $(LOCAL_PATH)/,, \

    $(wildcard $(LOCAL_PATH)/src/*.c) \

    $(wildcard $(LOCAL_PATH)/src/audio/*.c) \

    $(wildcard $(LOCAL_PATH)/src/audio/android/*.c) \

    $(wildcard $(LOCAL_PATH)/src/audio/dummy/*.c) \

    $(LOCAL_PATH)/src/atomic/SDL_atomic.c \

    $(LOCAL_PATH)/src/atomic/SDL_spinlock.c.arm \

    $(wildcard $(LOCAL_PATH)/src/core/android/*.c) \

    $(wildcard $(LOCAL_PATH)/src/cpuinfo/*.c) \

    $(wildcard $(LOCAL_PATH)/src/dynapi/*.c) \

    $(wildcard $(LOCAL_PATH)/src/events/*.c) \

    $(wildcard $(LOCAL_PATH)/src/file/*.c) \

    $(wildcard $(LOCAL_PATH)/src/haptic/*.c) \

    $(wildcard $(LOCAL_PATH)/src/haptic/dummy/*.c) \

    $(wildcard $(LOCAL_PATH)/src/joystick/*.c) \

    $(wildcard $(LOCAL_PATH)/src/joystick/android/*.c) \

    $(wildcard $(LOCAL_PATH)/src/loadso/dlopen/*.c) \

    $(wildcard $(LOCAL_PATH)/src/power/*.c) \

    $(wildcard $(LOCAL_PATH)/src/power/android/*.c) \

    $(wildcard $(LOCAL_PATH)/src/filesystem/dummy/*.c) \

    $(wildcard $(LOCAL_PATH)/src/render/*.c) \

    $(wildcard $(LOCAL_PATH)/src/render/*/*.c) \

    $(wildcard $(LOCAL_PATH)/src/stdlib/*.c) \

    $(wildcard $(LOCAL_PATH)/src/thread/*.c) \

    $(wildcard $(LOCAL_PATH)/src/thread/pthread/*.c) \

    $(wildcard $(LOCAL_PATH)/src/timer/*.c) \

    $(wildcard $(LOCAL_PATH)/src/timer/unix/*.c) \

    $(wildcard $(LOCAL_PATH)/src/video/*.c) \

    $(wildcard $(LOCAL_PATH)/src/video/android/*.c) \

    $(wildcard $(LOCAL_PATH)/src/test/*.c))

LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPES

LOCAL_LDLIBS := -ldl -lGLESv1_CM -lGLESv2 -llog -landroid

include $(BUILD_SHARED_LIBRARY)

###########################

#

# SDL static library

#

###########################

#LOCAL_MODULE := SDL2_static

#LOCAL_MODULE_FILENAME := libSDL2

#LOCAL_SRC_FILES += $(LOCAL_PATH)/src/main/android/SDL_android_main.c

#LOCAL_LDLIBS :=

#LOCAL_EXPORT_LDLIBS := -Wl,--undefined=Java_org_libsdl_app_SDLActivity_nativeInit -ldl -lGLESv1_CM -lGLESv2 -llog -landroid

#include $(BUILD_STATIC_LIBRARY)

二、参考[原]如何在Android用FFmpeg解码图像，在工程中新建一个ffmpeg文件夹，将与ffmpeg相关的头文件include进来。ffmpeg文件夹下的Android.mk内容：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := ffmpeg

LOCAL_SRC_FILES := /path/to/build/ffmpeg/libffmpeg.so

include $(PREBUILT_SHARED_LIBRARY)

三、新建player文件夹，用来编写解码与显示文件。player.c文件内容：

/*

 * SDL_Lesson.c

 *

 *  Created on: Aug 12, 2014

 *      Author: clarck

 */

#include <jni.h>

#include <android/native_window_jni.h>

#include "SDL.h"

#include "SDL_thread.h"

#include "SDL_events.h"

#include "../include/logger.h"

#include "../ffmpeg/include/libavcodec/avcodec.h"

#include "../ffmpeg/include/libavformat/avformat.h"

#include "../ffmpeg/include/libavutil/pixfmt.h"

#include "../ffmpeg/include/libswscale/swscale.h"

int main(int argc, char *argv[]) {

    char *file_path = argv[];

    LOGI("file_path:%s", file_path);

    AVFormatContext *pFormatCtx;

    AVCodecContext *pCodecCtx;

    AVCodec *pCodec;

    AVFrame *pFrame, *pFrameYUV;

    AVPacket *packet;

    uint8_t *out_buffer;

    SDL_Texture *bmp = NULL;

    SDL_Window *screen = NULL;

    SDL_Rect rect;

    SDL_Event event;

    static struct SwsContext *img_convert_ctx;

    int videoStream, i, numBytes;

    int ret, got_picture;

    av_register_all();

    pFormatCtx = avformat_alloc_context();

    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {

        LOGE("Could not initialize SDL - %s. \n", SDL_GetError());

        exit();

    }

    if (avformat_open_input(&pFormatCtx, file_path, NULL, NULL) != ) {

        LOGE("can't open the file. \n");

        return -;

    }

    if (avformat_find_stream_info(pFormatCtx, NULL) < ) {

        LOGE("Could't find stream infomation.\n");

        return -;

    }

    videoStream = ;

    for (i = ; i < pFormatCtx->nb_streams; i++) {

        if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {

            videoStream = i;

        }

    }

    LOGI("videoStream:%d", videoStream);

    if (videoStream == -) {

        LOGE("Didn't find a video stream.\n");

        return -;

    }

    pCodecCtx = pFormatCtx->streams[videoStream]->codec;

    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);

    if (pCodec == NULL) {

        LOGE("Codec not found.\n");

        return -;

    }

    if (avcodec_open2(pCodecCtx, pCodec, NULL) < ) {

        LOGE("Could not open codec.\n");

        return -;

    }

    pFrame = av_frame_alloc();

    pFrameYUV = av_frame_alloc();

    //---------------------------init sdl---------------------------//

    screen = SDL_CreateWindow("My Player Window", SDL_WINDOWPOS_UNDEFINED,

            SDL_WINDOWPOS_UNDEFINED, pCodecCtx->width, pCodecCtx->height,

            SDL_WINDOW_FULLSCREEN | SDL_WINDOW_OPENGL);

    SDL_Renderer *renderer = SDL_CreateRenderer(screen, -, );

    bmp = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12,

            SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);

    //-------------------------------------------------------------//

    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height,

            pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height,

            AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

    numBytes = avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width,

            pCodecCtx->height);

    out_buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));

    avpicture_fill((AVPicture *) pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P,

            pCodecCtx->width, pCodecCtx->height);

    rect.x = ;

    rect.y = ;

    rect.w = pCodecCtx->width;

    rect.h = pCodecCtx->height;

    int y_size = pCodecCtx->width * pCodecCtx->height;

    packet = (AVPacket *) malloc(sizeof(AVPacket));

    av_new_packet(packet, y_size);

    av_dump_format(pFormatCtx, , file_path, );

    while (av_read_frame(pFormatCtx, packet) >= ) {

        if (packet->stream_index == videoStream) {

            ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture,

                    packet);

            if (ret < ) {

                LOGE("decode error.\n");

                return -;

            }

            LOGI("got_picture:%d", got_picture);

            if (got_picture) {

                sws_scale(img_convert_ctx,

                        (uint8_t const * const *) pFrame->data,

                        pFrame->linesize, , pCodecCtx->height, pFrameYUV->data,

                        pFrameYUV->linesize);

                ////iPitch 计算yuv一行数据占的字节数

                //SDL_UpdateTexture(bmp, &rect, pFrameYUV->data[0], pFrameYUV->linesize[0]);

                SDL_UpdateYUVTexture(bmp, &rect,

                        pFrameYUV->data[], pFrameYUV->linesize[],

                        pFrameYUV->data[], pFrameYUV->linesize[],

                        pFrameYUV->data[], pFrameYUV->linesize[]);

                SDL_RenderClear(renderer);

                SDL_RenderCopy(renderer, bmp, &rect, &rect);

                SDL_RenderPresent(renderer);

            }

            SDL_Delay();

        }

        av_free_packet(packet);

        SDL_PollEvent(&event);

        switch (event.type) {

        case SDL_QUIT:

            SDL_Quit();

            exit();

            break;

        default:

            break;

        }

    }

    SDL_DestroyTexture(bmp);

    av_free(out_buffer);

    av_free(pFrameYUV);

    avcodec_close(pCodecCtx);

    avformat_close_input(&pFormatCtx);

    return ;

}

四、编写player文件夹下面的Android makefile，内容如下：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := player

SDL_PATH := ../SDL

FFMPEG_PATH := ../ffmpeg

LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(SDL_PATH)/include

LOCAL_C_INCLUDES += $(LOCAL_PATH)/$(FFMPEG_PATH)/include

# Add your application source files here...

LOCAL_SRC_FILES := $(SDL_PATH)/src/main/android/SDL_android_main.c

LOCAL_SRC_FILES += player.c

LOCAL_SHARED_LIBRARIES := SDL2

LOCAL_SHARED_LIBRARIES += ffmpeg

LOCAL_LDLIBS := -lGLESv1_CM -lGLESv2 -llog

include $(BUILD_SHARED_LIBRARY)

五、修改SDLActivity.java文件内容，用来加载libffmpeg.so以及libplayer.so，以及修改用来解码的文件路径。

// Load the .so

    static {

        System.loadLibrary("ffmpeg");

        System.loadLibrary("SDL2");

        //System.loadLibrary("SDL2_image");

        //System.loadLibrary("SDL2_mixer");

        //System.loadLibrary("SDL2_net");

        //System.loadLibrary("SDL2_ttf");

        System.loadLibrary("player");

    }

/**

    Simple nativeInit() runnable

*/

class SDLMain implements Runnable {

    @Override

    public void run() {

        // Runs SDL_main()

        String sdcard = Environment.getExternalStorageDirectory().getAbsolutePath();

        SDLActivity.nativeInit("/sdcard/a.mp4");

        //Log.v("SDL", "SDL thread terminated");

    }

}

工程项目截图：

运行效果截图：

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