按照这篇文章创建一个Android项目;
native方法
/**
*
* @param filePath 源文件目录
* @param surface surfaceview
* @param filterType 滤镜类型
* @return
*/
public native int filter(String filePath, Object surface, String filterType);
生成头文件：
javah com.example.zjf.ffmpegavfilter.FFmpeg
实现jni方法；
AVFilterContext *buffersink_ctx;
AVFilterContext *buffersrc_ctx;//认为它是AVFilter的一个实例就OK了
AVFilterGraph *filter_graph;
JNIEXPORT jint JNICALL Java_com_example_zjf_ffmpegavfilter_FFmpeg_filter
(JNIEnv* env, jobject obj, jstring filePath,jobject surface, jstring filterDescr){
LOGD("play");
const char *file_name = (env)->GetStringUTFChars(filePath, JNI_FALSE);
const char *filter_descr = (env)->GetStringUTFChars(filterDescr, JNI_FALSE);
av_register_all();
avfilter_register_all();////注册滤波器组件
AVFormatContext *pFormatCtx = avformat_alloc_context();
//打开视频文件
if (avformat_open_input(&pFormatCtx, file_name, NULL, NULL) != 0) {
LOGD("Couldn't open file:%s\n", file_name);
//goto end;
return -1; // Couldn't open file
}
//检索多媒体流信息
if (avformat_find_stream_info(pFormatCtx, NULL) < 0) {
LOGD("Couldn't find stream information.");
return -1;
}
//寻找视频流的第一帧
int videoStream = -1, i;
for (i = 0; i < pFormatCtx->nb_streams; i++) {
if (pFormatCtx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && videoStream < 0){
videoStream = i;
}
}
if (videoStream == -1) {
LOGD("Didn't find a video stream.");
return -1; // Didn't find a video stream
//goto end;
}
//获取codec上下文指针
AVCodecContext *pCodecCtx = avcodec_alloc_context3(NULL);
if (pCodecCtx == NULL)
{
LOGD("Could not allocate AVCodecContext\n");
return -1;
//goto end;
}
avcodec_parameters_to_context(pCodecCtx, pFormatCtx->streams[videoStream]->codecpar);
/**
* 开始初始化滤波器
*/
char args[512];
int ret;
//Filter的具体定义，只要是libavfilter中已注册的filter，
//就可以直接通过查询filter名字的方法获得其具体定义，所谓
//定义即filter的名称、功能描述、输入输出pad、相关回调函数等
AVFilter *buffersrc = avfilter_get_by_name("buffer"); /* 输入buffer filter */
AVFilter *buffersink = avfilter_get_by_name("buffersink"); /* 输出buffer filter */
//AVFilterInOut对应buffer和buffersink这两个首尾端的filter的输入输出
AVFilterInOut *outputs = avfilter_inout_alloc();
AVFilterInOut *inputs = avfilter_inout_alloc();
enum AVPixelFormat pix_fmts[] = {AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE };
AVRational time_base = pFormatCtx->streams[videoStream]->time_base;/* 时间基数 */
AVBufferSinkParams *buffersink_params;
filter_graph = avfilter_graph_alloc();
snprintf(args, sizeof(args),
"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
time_base.num, time_base.den,
pCodecCtx->sample_aspect_ratio.num, pCodecCtx->sample_aspect_ratio.den);
//根据指定的Filter，这里就是buffer，构造对应的初始化参数args，二者结合即可创建Filter的示例，并放入filter_graph中
ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
args, NULL, filter_graph);
if (ret < 0) {
LOGD("Cannot create buffer source === %d\n",ret);
return ret;
}
/* buffer video sink: to terminate the filter chain. */
buffersink_params = av_buffersink_params_alloc();
buffersink_params->pixel_fmts = pix_fmts;
ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
NULL, buffersink_params, filter_graph);
av_free(buffersink_params);
if (ret < 0) {
LOGD("Cannot create buffer sink\n");
return ret;
}
/* Endpoints for the filter graph. */
outputs->name = av_strdup("in");
outputs->filter_ctx = buffersrc_ctx;
outputs->pad_idx = 0;
outputs->next = NULL;
inputs->name = av_strdup("out");
inputs->filter_ctx = buffersink_ctx;
inputs->pad_idx = 0;
inputs->next = NULL;
//filter_descr是一个filter命令，例如"overlay=iw:ih"，该函数可以解析这个命令，
//然后自动完成FilterGraph中各个Filter之间的联接
if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_descr,
&inputs, &outputs, NULL)) < 0) {
LOGD("Cannot avfilter_graph_parse_ptr\n");
return ret;
}
if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) {//检查当前所构造的FilterGraph的完整性与可用性
LOGD("Cannot avfilter_graph_config\n");
return ret;
}
//寻找视频流的解码器
AVCodec *pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (pCodec == NULL) {
LOGD("Codec not found.");
//goto end;
return -1; // Codec not found
}
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
LOGD("Could not open codec.");
//goto end;
return -1; // Could not open codec
}
// 获取native window
ANativeWindow *nativeWindow = ANativeWindow_fromSurface(env, surface);
// 获取视频宽高
int videoWidth = pCodecCtx->width;
int videoHeight = pCodecCtx->height;
// 设置native window的buffer大小,可自动拉伸
ANativeWindow_setBuffersGeometry(nativeWindow, videoWidth, videoHeight,
WINDOW_FORMAT_RGBA_8888);
ANativeWindow_Buffer windowBuffer;
if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
LOGD("Could not open codec.");
//goto end;
return -1; // Could not open codec
}
AVFrame *pFrame = av_frame_alloc();
//用于渲染
AVFrame *pFrameRGBA = av_frame_alloc();
if (pFrameRGBA == NULL || pFrame == NULL) {
LOGD("Could not allocate video frame.");
//goto end;
return -1;
}
// buffer中数据就是用于渲染的,且格式为RGBA
int numBytes = av_image_get_buffer_size(AV_PIX_FMT_RGBA, pCodecCtx->width, pCodecCtx->height,
1);
uint8_t *buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
av_image_fill_arrays(pFrameRGBA->data, pFrameRGBA->linesize, buffer, AV_PIX_FMT_RGBA,
pCodecCtx->width, pCodecCtx->height, 1);
// 由于解码出来的帧格式不是RGBA的,在渲染之前需要进行格式转换
struct SwsContext *sws_ctx = sws_getContext(pCodecCtx->width,
pCodecCtx->height,
pCodecCtx->pix_fmt,
pCodecCtx->width,
pCodecCtx->height,
AV_PIX_FMT_RGBA,
SWS_BILINEAR,
NULL,
NULL,
NULL);
AVPacket packet;
while (av_read_frame(pFormatCtx, &packet) >= 0) {
if(again){
goto again;
}
if (packet.stream_index == videoStream) {
//解码该帧
if(avcodec_send_packet(pCodecCtx, &packet) == 0){
while (avcodec_receive_frame(pCodecCtx, pFrame) == 0) {
pFrame->pts = av_frame_get_best_effort_timestamp(pFrame);//获取PTS
//把解码后视频帧添加到filter_graph
if (av_buffersrc_add_frame(buffersrc_ctx, pFrame) < 0) {
LOGD("Could not av_buffersrc_add_frame");
break;
}
//把滤波后的视频帧从filter graph取出来
ret = av_buffersink_get_frame(buffersink_ctx, pFrame);
if (ret < 0) {
LOGD("Could not av_buffersink_get_frame");
break;
}
ANativeWindow_lock(nativeWindow, &windowBuffer, 0);
//格式转换
sws_scale(sws_ctx, (uint8_t const *const *) pFrame->data,
pFrame->linesize, 0, pCodecCtx->height,
pFrameRGBA->data, pFrameRGBA->linesize);
//获取stride
uint8_t *dst = (uint8_t *) windowBuffer.bits;
int dstStride = windowBuffer.stride * 4;
uint8_t *src = (pFrameRGBA->data[0]);
int srcStride = pFrameRGBA->linesize[0];
//由于window的stride和帧的stride不同,因此需要逐行复制
int h;
for (h = 0; h < videoHeight; h++) {
memcpy(dst + h * dstStride, src + h * srcStride, srcStride);
}
ANativeWindow_unlockAndPost(nativeWindow);
}
}
}
av_packet_unref(&packet);
}
is_playing = 0;
//释放内存以及关闭文件
av_free(buffer);
av_free(pFrameRGBA);
av_free(pFrame);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
avfilter_free(buffersrc_ctx);
avfilter_free(buffersink_ctx);
avfilter_graph_free(&filter_graph);
free(buffer);
free(sws_ctx);
free(&windowBuffer);
ANativeWindow_release(nativeWindow);
(env)->ReleaseStringUTFChars(filePath, file_name);
(env)->ReleaseStringUTFChars(filterDescr, filter_descr);
LOGE("do release...");
again:
again = 0;
LOGE("play again...");
return ret;
}
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