ffmpeg實踐學習

• android全平臺編譯ffmpeg以及x264與fdk-aac實踐
• ubuntu下使用nginx和nginx-rtmp-module配置直播推流伺服器
• android全平臺編譯ffmpeg合併為單個庫實踐
• android-studio使用cmake編譯ffmpeg實踐
• android全平臺編譯ffmpeg視訊解碼器實踐
• android全平臺編譯ffmpeg支援命令列實踐

本文目錄

• 概述
• 配置環境
• 新建streamer工程
• 播放串流

概述

還是先從最簡單的搞起來，先從最基本的視訊推流開始，要知道在電腦上使用ffmpeg

ffmpeg -re -i input.mp4 -vcodec copy -f flv rtmp://192.168.1.102:1935/onzhou/live

配置環境

作業系統: ubuntu 16.05

注意: ffmpeg庫的編譯使用的是android-ndk-r10e版本，使用高版本編譯會報錯。

而android-studio工程中配合cmake使用的版本則是android-ndk-r16b版本

新建工程ffmpeg-single-streamer

• build.gradle配置比較簡單，可以參考之前的文章

• 新建CMakeLists.txt檔案，配置如下

cmake_minimum_required(VERSION 3.4.1)


add_library(ffmpeg-streamer
           SHARED
           src/main/cpp/ffmpeg_streamer.c)

find_library(log-lib
            log)

#獲取上級目錄
get_filename_component(PARENT_DIR ${CMAKE_SOURCE_DIR}
 
 PATH)
set(LIBRARY_DIR ${PARENT_DIR}/ffmpeg-single)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
set(CMAKE_VERBOSE_MAKEFILE on)

add_library(ffmpeg-single
           SHARED
           IMPORTED)

set_target_properties(ffmpeg-single
                    PROPERTIES IMPORTED_LOCATION
                    ${LIBRARY_DIR}/libs/${ANDROID_ABI}/libffmpeg.so
                    )

#標頭檔案
include_directories(${LIBRARY_DIR}/libs/${ANDROID_ABI}/include)

target_link_libraries(ffmpeg-streamer ffmpeg-single ${log-lib})

• 新建NowStreamer.java檔案

package com.onzhou.ffmpeg.streamer;

public class NowStreamer {

    static {
        System.loadLibrary("ffmpeg");
        System.loadLibrary("ffmpeg-streamer");
    }

    public native int startPublish(String input, String output);

}

• 在src/main/cpp目錄新建原始檔ffmpeg_streamer.c

#include <jni.h>
#include <stdio.h>
#include <time.h>
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavfilter/avfilter.h"
#include "libavutil/log.h"

#ifdef ANDROID

#include <android/log.h>
#include <libavutil/time.h>

#define LOG_TAG    "NowStreamer"
#define LOGE(format, ...)  __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, format, ##__VA_ARGS__)
#define LOGI(format, ...)  __android_log_print(ANDROID_LOG_INFO,  LOG_TAG, format, ##__VA_ARGS__)
#else
#define LOGE(format, ...)  printf(LOG_TAG format "\n", ##__VA_ARGS__)
#define LOGI(format, ...)  printf(LOG_TAG format "\n", ##__VA_ARGS__)
#endif

//輸出日誌
void log_callback(void *ptr, int level, const char *fmt, va_list vl) {
    //寫入日誌檔案
    FILE *fp = fopen("/storage/emulated/0/av_log.txt", "a+");
    if (fp) {
        vfprintf(fp, fmt, vl);
        fflush(fp);
        fclose(fp);
    }
    //LOGE(fmt, vl);
}

JNIEXPORT jint JNICALL Java_com_onzhou_ffmpeg_streamer_NowStreamer_startPublish
        (JNIEnv *env, jobject obj, jstring input_jstr, jstring output_jstr) {

    AVOutputFormat *ofmt = NULL;
    AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
    AVPacket pkt;

    int ret, i;
    char input_str[500] = {0};
    char output_str[500] = {0};
    char info[1000] = {0};

    sprintf(input_str, "%s", (*env)->GetStringUTFChars(env, input_jstr, NULL));
    sprintf(output_str, "%s", (*env)->GetStringUTFChars(env, output_jstr, NULL));

    //日誌回撥寫入檔案
    av_log_set_callback(log_callback);

    av_register_all();
    //網路初始化
    avformat_network_init();

    //Input
    if ((ret = avformat_open_input(&ifmt_ctx, input_str, 0, 0)) < 0) {
        LOGE("Could not open input file.");
        goto end;
    }
    if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
        LOGE("Failed to retrieve input stream information");
        goto end;
    }

    int videoindex = -1;
    for (i = 0; i < ifmt_ctx->nb_streams; i++)
        if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            videoindex = i;
            break;
        }
    //Output
    avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", output_str); //RTMP
    //avformat_alloc_output_context2(&ofmt_ctx, NULL, "mpegts", output_str);//UDP

    if (!ofmt_ctx) {
        LOGE("Could not create output context\n");
        ret = AVERROR_UNKNOWN;
        goto end;
    }
    ofmt = ofmt_ctx->oformat;
    for (i = 0; i < ifmt_ctx->nb_streams; i++) {
        //Create output AVStream according to input AVStream
        AVStream *in_stream = ifmt_ctx->streams[i];
        AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
        if (!out_stream) {
            LOGE("Failed allocating output stream\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }
        //Copy the settings of AVCodecContext
        ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
        if (ret < 0) {
            LOGE("Failed to copy context from input to output stream codec context\n");
            goto end;
        }
        out_stream->codec->codec_tag = 0;
        if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
            out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
    }

    //Open output URL
    if (!(ofmt->flags & AVFMT_NOFILE)) {
        ret = avio_open(&ofmt_ctx->pb, output_str, AVIO_FLAG_WRITE);
        if (ret < 0) {
            LOGE("Could not open output URL '%s'", output_str);
            goto end;
        }
    }
    //Write file header
    ret = avformat_write_header(ofmt_ctx, NULL);
    if (ret < 0) {
        LOGE("Error occurred when opening output URL\n");
        goto end;
    }

    int frame_index = 0;

    int64_t start_time = av_gettime();
    while (1) {
        AVStream *in_stream, *out_stream;
        //Get an AVPacket
        ret = av_read_frame(ifmt_ctx, &pkt);
        if (ret < 0)
            break;
        //FIX：No PTS (Example: Raw H.264)
        //Simple Write PTS
        if (pkt.pts == AV_NOPTS_VALUE) {
            //Write PTS
            AVRational time_base1 = ifmt_ctx->streams[videoindex]->time_base;
            //Duration between 2 frames (us)
            int64_t calc_duration =
                    (double) AV_TIME_BASE / av_q2d(ifmt_ctx->streams[videoindex]->r_frame_rate);
            //Parameters
            pkt.pts = (double) (frame_index * calc_duration) /
                      (double) (av_q2d(time_base1) * AV_TIME_BASE);
            pkt.dts = pkt.pts;
            pkt.duration = (double) calc_duration / (double) (av_q2d(time_base1) * AV_TIME_BASE);
        }
        //Important:Delay
        if (pkt.stream_index == videoindex) {
            AVRational time_base = ifmt_ctx->streams[videoindex]->time_base;
            AVRational time_base_q = {1, AV_TIME_BASE};
            int64_t pts_time = av_rescale_q(pkt.dts, time_base, time_base_q);
            int64_t now_time = av_gettime() - start_time;
            if (pts_time > now_time)
                av_usleep(pts_time - now_time);

        }

        in_stream = ifmt_ctx->streams[pkt.stream_index];
        out_stream = ofmt_ctx->streams[pkt.stream_index];
        /* copy packet */
        //Convert PTS/DTS
        pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base,
                                   AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
        pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base,
                                   AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
        pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
        pkt.pos = -1;
        //Print to Screen
        if (pkt.stream_index == videoindex) {
            LOGE("Send %8d video frames to output URL\n", frame_index);
            frame_index++;
        }
        //ret = av_write_frame(ofmt_ctx, &pkt);
        ret = av_interleaved_write_frame(ofmt_ctx, &pkt);

        if (ret < 0) {
            LOGE("Error muxing packet\n");
            break;
        }
        av_free_packet(&pkt);

    }
    //Write file trailer
    av_write_trailer(ofmt_ctx);
end:
    avformat_close_input(&ifmt_ctx);
    /* close output */
    if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
        avio_close(ofmt_ctx->pb);
    avformat_free_context(ofmt_ctx);
    if (ret < 0 && ret != AVERROR_EOF) {
        LOGE("Error occurred.\n");
        return -1;
    }
    return 0;
}

推流伺服器的搭建，可以參考之前的文章

public void onStartClick(View view) {
		if (nowStreamer == null) {
				nowStreamer = new NowStreamer();
		}
		if (publishDisposable == null) {
				publishDisposable = Schedulers.newThread().scheduleDirect(new Runnable() {
						@Override
						public void run() {
							  //推流本地的一個mp4檔案
								final File intputVideo = new File(getExternalFilesDir(null), "input.mp4");
								nowStreamer.startPublish(intputVideo.getAbsolutePath(), PUBLISH_ADDRESS);
						}
				});
		}
}

編譯打包執行，開始推流，我們在區域網中使用vlc播放器，開啟網路串流

rtmp://192.168.1.102:1935/onzhou/live

專案地址:
https://github.com/byhook/ffmpeg4android

參考雷神:
https://blog.csdn.net/leixiaohua1020/article/details/47056051