在上一章Android本地視頻播放器開發--SDL編譯編譯中編譯出sdl的支持庫，當時我們使用的2.0，但是有些api被更改了，所以在以下的使用者中我們使用SDL1.3的庫，這個庫我會傳上源碼以及編譯出的庫，接下來這張我們使用ffmpeg解碼視頻文件中的視頻幀同時使用SDL去顯示。

1、Decodec_Video.c 這是我視頻解碼的文件，其中內容如下:

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#include <stdio.h> #include <android/log.h>#ifdef __MINGW32__ #undef main /* Prevents SDL from overriding main() */ #endif#include "../SDL/include/SDL.h" #include "../SDL/include/SDL_thread.h"#include "VideoPlayerDecode.h" #include "../ffmpeg/libavutil/avutil.h" #include "../ffmpeg/libavcodec/avcodec.h" #include "../ffmpeg/libavformat/avformat.h" #include "../ffmpeg/libswscale/swscale.h"AVFormatContext *pFormatCtx; int i, videoStream; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame; AVPacket packet; int frameFinished; float aspect_ratio;static struct SwsContext *img_convert_ctx; SDL_Surface *screen; SDL_Overlay *bmp; SDL_Rect rect; SDL_Event event;JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayer (JNIEnv *env, jclass clz, jstring fileName) {const char* local_title = (*env)->GetStringUTFChars(env, fileName, NULL);av_register_all();//注冊所有支持的文件格式以及編解碼器if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());exit(1);}if(avformat_open_input(&pFormatCtx, local_title, NULL, NULL) != 0)return -1;if(avformat_find_stream_info(pFormatCtx, NULL) < 0)return -1;av_dump_format(pFormatCtx, -1, local_title, 0);videoStream=-1;for(i=0; i<pFormatCtx->nb_streams; i++)if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {videoStream=i;break;}if(videoStream==-1)return -1; // Didn't find a video stream// Get a pointer to the codec context for the video streampCodecCtx=pFormatCtx->streams[videoStream]->codec;// Find the decoder for the video streampCodec=avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec==NULL) {fprintf(stderr, "Unsupported codec!\n");return -1; // Codec not found}if(avcodec_open2(pCodecCtx, pCodec, NULL) < 0)return -1;pFrame = avcodec_alloc_frame();if(pFrame == NULL)return -1;// Make a screen to put our video #ifndef __DARWIN__screen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 0, 0); #elsescreen = SDL_SetVideoMode(pCodecCtx->width, pCodecCtx->height, 24, 0); #endifif(!screen) {fprintf(stderr, "SDL: could not set video mode - exiting\n");exit(1);}// Allocate a place to put our YUV image on that screenbmp = SDL_CreateYUVOverlay(pCodecCtx->width,pCodecCtx->height,SDL_YV12_OVERLAY,screen);img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL); // Read frames and save first five frames to diski=0;while(av_read_frame(pFormatCtx, &packet)>=0) {// Is this a packet from the video stream?if(packet.stream_index==videoStream) {avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);// Did we get a video frame?if(frameFinished) {SDL_LockYUVOverlay(bmp);AVPicture *pict;pict->data[0] = bmp->pixels[0];pict->data[1] = bmp->pixels[2];pict->data[2] = bmp->pixels[1];pict->linesize[0] = bmp->pitches[0];pict->linesize[1] = bmp->pitches[2];pict->linesize[2] = bmp->pitches[1];sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pict->data, pict->linesize);SDL_UnlockYUVOverlay(bmp);rect.x = 0;rect.y = 0;rect.w = pCodecCtx->width;rect.h = pCodecCtx->height;SDL_DisplayYUVOverlay(bmp, &rect);}}// Free the packet that was allocated by av_read_frameav_free_packet(&packet);SDL_PollEvent(&event);switch(event.type) {case SDL_QUIT:SDL_Quit();exit(0);break;default:break;}}// Free the YUV frameav_free(pFrame);// Close the codecavcodec_close(pCodecCtx);// Close the video fileav_close_input_file(pFormatCtx); }

2、編譯結果如下:

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root@zhangjie:/Graduation/jni# ndk-build Install : libSDL.so => libs/armeabi/libSDL.so Install : libffmpeg-neon.so => libs/armeabi/libffmpeg-neon.so Compile arm : ffmpeg-test-neon <= Decodec_Video.c /Graduation/jni/jniffmpeg/Decodec_Video.c: In function 'Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayer': /Graduation/jni/jniffmpeg/Decodec_Video.c:106:1: warning: passing argument 2 of 'sws_scale' from incompatible pointer type [enabled by default] /Graduation/jni/jniffmpeg/../ffmpeg/libswscale/swscale.h:237:5: note: expected 'uint8_t const * const*' but argument is of type 'uint8_t **' /Graduation/jni/jniffmpeg/Decodec_Video.c:137:2: warning: 'av_close_input_file' is deprecated (declared at /Graduation/jni/jniffmpeg/../ffmpeg/libavformat/avformat.h:1533) [-Wdeprecated-declarations] SharedLibrary : libffmpeg-test-neon.so Install : libffmpeg-test-neon.so => libs/armeabi/libffmpeg-test-neon.so

3、SDL1.3源碼

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http://download.csdn.net/detail/jwzhangjie/5596453

4、之前在Android本地視頻播放器開發--NDK編譯FFmpeg中沒有添加swscale功能，所以需要重新編譯ffmpeg，其腳本如下:

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NDK=/opt/android-ndk-r8d PLATFORM=$NDK/platforms/android-8/arch-arm/ PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86 LOCAL_ARM_NEON=true CPU=armv7-a OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -mcpu=cortex-a8" PREFIX=./android/$CPU ./configure --target-os=linux \--prefix=$PREFIX \--enable-cross-compile \--arch=arm \--enable-nonfree \--enable-asm \--cpu=cortex-a8 \--enable-neon \--cc=$PREBUILT/bin/arm-linux-androideabi-gcc \--cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \--nm=$PREBUILT/bin/arm-linux-androideabi-nm \--sysroot=$PLATFORM \--extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 $OPTIMIZE_CFLAGS " \--disable-shared \--enable-static \--extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \--disable-ffmpeg \--disable-ffplay \--disable-ffprobe \--disable-ffserver \--disable-encoders \--enable-avformat \--disable-optimizations \--disable-doc \--enable-pthreads \--disable-yasm \--enable-zlib \--enable-pic \--enable-small#make clean make -j4 install$PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o$PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -soname libffmpeg-neon.so -shared -nostdlib -z noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg-neon.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libavfilter/libavfilter.a libswresample/libswresample.a libswscale/libswscale.a libavdevice/libavdevice.a -lc -lm -lz -ldl -llog --warn-once --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a

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