Android本地视频播放器开发--视频解码

在上一章Android本地视频播放器开发--SDL编译编译中编译出sdl的支持库，当时我们使用的2.0，但是有些api被更改了，所以在以下的使用者中我们使用SDL1.3的库，这个库我会传上源码以及编译出的库，接下来这张我们使用ffmpeg解码视频文件中的视频帧同时使用SDL去显示。

1、Decodec_Video.c 这是我视频解码的文件，其中内容如下:

#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();//注册所有支持的文件格式以及编解码器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、编译结果如下:

root@zhangjie:/Graduation/jni# ndk-buildInstall        : libSDL.so => libs/armeabi/libSDL.soInstall        : libffmpeg-neon.so => libs/armeabi/libffmpeg-neon.soCompile 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.soInstall        : libffmpeg-test-neon.so => libs/armeabi/libffmpeg-test-neon.so

3、SDL1.3源码

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

4、之前在Android本地视频播放器开发--NDK编译FFmpeg中没有添加swscale功能，所以需要重新编译ffmpeg，其脚本如下:

NDK=/opt/android-ndk-r8dPLATFORM=$NDK/platforms/android-8/arch-arm/PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86LOCAL_ARM_NEON=trueCPU=armv7-aOPTIMIZE_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$PLATFORM/usr/lib  -nostdlib -lc -lm -ldl -llog" \    --disable-ffmpeg \    --disable-ffplay \    --disable-ffprobe \    --disable-ffserver \    --disable-encoders \    --enable-avformat \    --disable-optimizations \    --disable-doc \    --enable-pthreads \    --disable-yasm \    --enable-zlib \    --enable-pic \    --enable-small#make cleanmake  -j4 install$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