基于FFmpeg 和 OpenGL 的视频播放 【C++】

环境：

GLFW版本为 2.7.9

GLM版本为 0.9.4.6（需自己编译生成 dll 和 lib）

OpenGL 3.+

以下代码仅仅通过ffmpeg解码视频（没有处理音频流），然后通过OpenGL进行显示（或通过Shader对视频帧进行处理）

代码如下：

std::string const vert_shader_source = "#version 150\n""in vec3 vertex;\n""in vec2 texCoord0;\n""uniform mat4 mvpMatrix;\n""out vec2 texCoord;\n""void main() {\n""gl_Position = mvpMatrix * vec4(vertex, 1.0);\n""texCoord = texCoord0;\n""}\n";std::string const frag_shader_source ="#version 150\n""uniform sampler2D frameTex;\n""in vec2 texCoord;\n""out vec4 fragColor;\n""void main() {\n""fragColor = texture(frameTex, texCoord);\n""}\n";#define BUFFER_OFFSET(i) ((char *)NULL + (i))// attribute indicesenum {VERTICES = 0,TEX_COORDS};// uniform indicesenum {MVP_MATRIX = 0,FRAME_TEX};// app data structuretypedef struct {AVFormatContext *fmt_ctx;int stream_idx;AVStream *video_stream;AVCodecContext *codec_ctx;AVCodec *decoder;AVPacket *packet;AVFrame *av_frame;AVFrame *gl_frame;struct SwsContext *conv_ctx;GLuint vao;GLuint vert_buf;GLuint elem_buf;GLuint frame_tex;GLuint program;GLuint attribs[2];GLuint uniforms[2];} AppData;// initialize the app data structurevoid initializeAppData(AppData *data) {data->fmt_ctx = NULL;data->stream_idx = -1;data->video_stream = NULL;data->codec_ctx = NULL;data->decoder = NULL;data->av_frame = NULL;data->gl_frame = NULL;data->conv_ctx = NULL;}// clean up the app data structurevoid clearAppData(AppData *data) {if (data->av_frame) av_free(data->av_frame);if (data->gl_frame) av_free(data->gl_frame);if (data->packet) av_free(data->packet);if (data->codec_ctx) avcodec_close(data->codec_ctx);if (data->fmt_ctx) avformat_free_context(data->fmt_ctx);glDeleteVertexArrays(1, &data->vao);glDeleteBuffers(1, &data->vert_buf);glDeleteBuffers(1, &data->elem_buf);glDeleteTextures(1, &data->frame_tex);initializeAppData(data);}// read a video framebool readFrame(AppData *data) {do {if (av_read_frame(data->fmt_ctx, data->packet) < 0) {av_free_packet(data->packet);return false;}if (data->packet->stream_index == data->stream_idx) {int frame_finished = 0;if (avcodec_decode_video2(data->codec_ctx, data->av_frame, &frame_finished, data->packet) < 0) {av_free_packet(data->packet);return false;}if (frame_finished) {if (!data->conv_ctx) {data->conv_ctx = sws_getContext(data->codec_ctx->width, data->codec_ctx->height, data->codec_ctx->pix_fmt, data->codec_ctx->width, data->codec_ctx->height, PIX_FMT_RGB24,SWS_BICUBIC, NULL, NULL, NULL);}sws_scale(data->conv_ctx, data->av_frame->data, data->av_frame->linesize, 0, data->codec_ctx->height, data->gl_frame->data, data->gl_frame->linesize);glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, data->codec_ctx->width, data->codec_ctx->height, GL_RGB, GL_UNSIGNED_BYTE, data->gl_frame->data[0]);}}av_free_packet(data->packet);} while (data->packet->stream_index != data->stream_idx);return true;}bool buildShader(std::string const &shader_source, GLuint &shader, GLenum type) {int size = shader_source.length();shader = glCreateShader(type);char const *c_shader_source = shader_source.c_str();glShaderSource(shader, 1, (GLchar const **)&c_shader_source, &size);glCompileShader(shader);GLint status;glGetShaderiv(shader, GL_COMPILE_STATUS, &status);if (status != GL_TRUE) {std::cout << "failed to compile shader" << std::endl;int length;glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);char *log = new char[length];glGetShaderInfoLog(shader, length, &length, log);std::cout << log << std::endl;delete[] log;return false;}return true;}// initialize shadersbool buildProgram(AppData *data) {GLuint v_shader, f_shader;if (!buildShader(vert_shader_source, v_shader, GL_VERTEX_SHADER)) {std::cout << "failed to build vertex shader" << std::endl;return false;}if (!buildShader(frag_shader_source, f_shader, GL_FRAGMENT_SHADER)) {std::cout << "failed to build fragment shader" << std::endl;return false;} data->program = glCreateProgram();glAttachShader(data->program, v_shader);glAttachShader(data->program, f_shader);glLinkProgram(data->program);GLint status;glGetProgramiv(data->program, GL_LINK_STATUS, &status);if (status != GL_TRUE) {std::cout << "failed to link program" << std::endl;int length;glGetProgramiv(data->program, GL_INFO_LOG_LENGTH, &length);char *log = new char[length];glGetShaderInfoLog(data->program, length, &length, log);std::cout << log << std::endl;delete[] log;return false;}data->uniforms[MVP_MATRIX] = glGetUniformLocation(data->program, "mvpMatrix");data->uniforms[FRAME_TEX] = glGetUniformLocation(data->program, "frameTex");data->attribs[VERTICES] = glGetAttribLocation(data->program, "vertex");data->attribs[TEX_COORDS] = glGetAttribLocation(data->program, "texCoord0");return true;}// draw frame in opengl contextvoid drawFrame(AppData *data) {glClear(GL_COLOR_BUFFER_BIT);glBindTexture(GL_TEXTURE_2D, data->frame_tex);glBindVertexArray(data->vao);glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));glBindVertexArray(0);glfwSwapBuffers();}int main(int argc, char *argv[]) {if (argc < 2) {std::cout << "provide a filename" << std::endl;return -1;}// initialize libavav_register_all();avformat_network_init();// initialize custom data structureAppData data;initializeAppData(&data);// open videoif (avformat_open_input(&data.fmt_ctx, argv[1], NULL, NULL) < 0) {std::cout << "failed to open input" << std::endl;clearAppData(&data);return -1;}// find stream infoif (avformat_find_stream_info(data.fmt_ctx, NULL) < 0) {std::cout << "failed to get stream info" << std::endl;clearAppData(&data);return -1;}// dump debug infoav_dump_format(data.fmt_ctx, 0, argv[1], 0);// find the video stream    for (unsigned int i = 0; i < data.fmt_ctx->nb_streams; ++i)    {        if (data.fmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)        {            data.stream_idx = i;            break;        }    }    if (data.stream_idx == -1)    {std::cout << "failed to find video stream" << std::endl;clearAppData(&data);return -1;    }    data.video_stream = data.fmt_ctx->streams[data.stream_idx];    data.codec_ctx = data.video_stream->codec;// find the decoder    data.decoder = avcodec_find_decoder(data.codec_ctx->codec_id);    if (data.decoder == NULL)    {std::cout << "failed to find decoder" << std::endl;clearAppData(&data);return -1;    }// open the decoder    if (avcodec_open2(data.codec_ctx, data.decoder, NULL) < 0)    {    std::cout << "failed to open codec" << std::endl;        clearAppData(&data);        return -1;    }// allocate the video frames    data.av_frame = avcodec_alloc_frame();    data.gl_frame = avcodec_alloc_frame();    int size = avpicture_get_size(PIX_FMT_RGB24, data.codec_ctx->width,     data.codec_ctx->height);    uint8_t *internal_buffer = (uint8_t *)av_malloc(size * sizeof(uint8_t));    avpicture_fill((AVPicture *)data.gl_frame, internal_buffer, PIX_FMT_RGB24,     data.codec_ctx->width, data.codec_ctx->height);data.packet = (AVPacket *)av_malloc(sizeof(AVPacket));// initialize glfwif (!glfwInit()) {std::cout << "glfw failed to init" << std::endl;glfwTerminate();clearAppData(&data);return -1;}// open a windowfloat aspect = (float)data.codec_ctx->width / (float)data.codec_ctx->height;int adj_width = aspect * 300;int adj_height = 300;glfwOpenWindowHint(GLFW_OPENGL_VERSION_MAJOR, 3);glfwOpenWindowHint(GLFW_OPENGL_VERSION_MINOR, 2);glfwOpenWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);glfwOpenWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);if (!glfwOpenWindow(adj_width, adj_height, 0, 0, 0, 0, 0, 0, GLFW_WINDOW)) {std::cout << "failed to open window" << std::endl;glfwTerminate();clearAppData(&data);return -1;}// initialize openglglClearColor(0.0f, 0.0f, 0.0f, 0.0f);glEnable(GL_TEXTURE_2D);// initialize shadersif (!buildProgram(&data)) {std::cout << "failed to initialize shaders" << std::endl;glfwTerminate();clearAppData(&data);return -1;}glUseProgram(data.program);// initialize renderableglGenVertexArrays(1, &data.vao);glBindVertexArray(data.vao);glGenBuffers(1, &data.vert_buf);glBindBuffer(GL_ARRAY_BUFFER, data.vert_buf);float quad[20] = {-1.0f,  1.0f, 0.0f, 0.0f, 0.0f,-1.0f, -1.0f, 0.0f, 0.0f, 1.0f, 1.0f, -1.0f, 0.0f, 1.0f, 1.0f, 1.0f,  1.0f, 0.0f, 1.0f, 0.0f};glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);glVertexAttribPointer(data.attribs[VERTICES], 3, GL_FLOAT, GL_FALSE, 20, BUFFER_OFFSET(0));glEnableVertexAttribArray(data.attribs[VERTICES]);glVertexAttribPointer(data.attribs[TEX_COORDS], 2, GL_FLOAT, GL_FALSE, 20,BUFFER_OFFSET(12));glEnableVertexAttribArray(data.attribs[TEX_COORDS]);  glGenBuffers(1, &data.elem_buf);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, data.elem_buf);unsigned char elem[6] = {0, 1, 2,0, 2, 3};glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elem), elem, GL_STATIC_DRAW);glBindVertexArray(0);glActiveTexture(GL_TEXTURE0);glGenTextures(1, &data.frame_tex);glBindTexture(GL_TEXTURE_2D, data.frame_tex);glPixelStorei(GL_UNPACK_ALIGNMENT, 1);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, data.codec_ctx->width, data.codec_ctx->height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);glUniform1i(data.uniforms[FRAME_TEX], 0);glm::mat4 mvp = glm::ortho(-1.0f, 1.0f, -1.0f, 1.0f, -1.0f, 1.0f);glUniformMatrix4fv(data.uniforms[MVP_MATRIX], 1, GL_FALSE, glm::value_ptr(mvp));bool running = true;// run the application mainloopwhile (readFrame(&data) && running) {running = !glfwGetKey(GLFW_KEY_ESC) && glfwGetWindowParam(GLFW_OPENED);drawFrame(&data);}    avformat_close_input(&data.fmt_ctx);// clean upglfwTerminate();clearAppData(&data);}

效果图：