### 1. 编译按照教程编译即可: https://gitee.com/openharmony-sig/tpc_c_cplusplus ``` ./build ffmpeg ``` 按照教程把编译好的.a文件复制到项目的cpp下面, 记得复制一些必要的.h文件到include里面去 ![image.png](https://p9-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/c903f5ed967c4de19d606632d1e52f6b~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg54ix5ou85omN5Lya6LWiMDA3:q75.awebp?rk3s=f64ab15b&x-expires=1760778658&x-signature=pzTcNmJFMmo%2B4DewZAjPZbFtNUk%3D) 复制源码里面的fftool下面的 ``` ffmpeg.h cmdutils.h cmdutils.c ffmpeg.c ffmpeg_filter.c ffmpeg_opt.c ffmpeg_hw.c ``` 复制编译好的config.h, 差不多是下面的路径 ``` tpc_c_cplusplus/thirdparty/FFmpeg/FFmpeg-arm64-v8a-build/FFmpeg-n4.1/config.h ``` 然后新建一个exception.h ``` #ifndef EXCEPTION_H #define EXCEPTION_H #include /** Holds information to implement exception handling. */ extern __thread jmp_buf ex_buf__; #endif // EXCEPTION_H ``` 继续新建exception.c ``` #include #include /** Holds information to implement exception handling. */ __thread jmp_buf ex_buf__; ``` ### 2. 修改源码 2.1 修复ffmpeg.c, 把int main方法改名字, 记得在头文件ffmpeg.h里面定义 ``` int exe_ffmpeg_cmd(int argc, char **argv) ``` 2.2 在ffmpeg.c的顶部添加 ``` extern __thread volatile int longjmp_value; ``` 2.3 修改cmdutils.c ``` void exit_program(int ret) { if (program_exit) program_exit(ret); // exit disabled and replaced with longjmp, exit value stored in longjmp_value // exit(ret); longjmp_value = ret; longjmp(ex_buf__, ret); } ``` 2.4 修改ffmpeg.c的exe_ffmpeg_cmd方法 ``` int exe_ffmpeg_cmd(int argc, char **argv, Callbacks *callback) { int i, ret; BenchmarkTimeStamps ti; int savedCode = setjmp(ex_buf__); if (savedCode == 0) { init_dynload(); register_exit(ffmpeg_cleanup); setvbuf(stderr, NULL, _IONBF, 0); /* win32 runtime needs this */ av_log_set_flags(AV_LOG_SKIP_REPEATED); parse_loglevel(argc, argv, options); if (argc > 1 && !strcmp(argv[1], "-d")) { run_as_daemon = 1; av_log_set_callback(log_callback_null); argc--; argv++; } #if CONFIG_AVDEVICE avdevice_register_all(); #endif avformat_network_init(); show_banner(argc, argv, options); /* parse options and open all input/output files */ ret = ffmpeg_parse_options(argc, argv); if (ret < 0) exit_program(ret); if (nb_output_files <= 0 && nb_input_files == 0) { show_usage(); av_log(NULL, AV_LOG_WARNING, "Use -h to get full help or, even better, run 'man %s'\n", program_name); exit_program(1); } /* file converter / grab */ if (nb_output_files <= 0) { av_log(NULL, AV_LOG_FATAL, "At least one output file must be specified\n"); exit_program(1); } for (i = 0; i < nb_output_files; i++) { if (strcmp(output_files[i]->ctx->oformat->name, "rtp")) want_sdp = 0; } current_time = ti = get_benchmark_time_stamps(); ret = transcode(); if (ret < 0) { exit_program(ret); } if (do_benchmark) { int64_t utime, stime, rtime; current_time = get_benchmark_time_stamps(); utime = current_time.user_usec - ti.user_usec; stime = current_time.sys_usec - ti.sys_usec; rtime = current_time.real_usec - ti.real_usec; av_log(NULL, AV_LOG_INFO, "bench: utime=%0.3fs stime=%0.3fs rtime=%0.3fs\n", utime / 1000000.0, stime / 1000000.0, rtime / 1000000.0); } av_log(NULL, AV_LOG_DEBUG, "%" PRIu64 " frames successfully decoded, %" PRIu64 " decoding errors\n", decode_error_stat[0], decode_error_stat[1]); if ((decode_error_stat[0] + decode_error_stat[1]) * max_error_rate < decode_error_stat[1]) exit_program(69); exit_program(received_nb_signals ? 255 : main_return_code); } else { main_return_code = (received_nb_signals) ? 255 : longjmp_value; } return main_return_code; } ``` ### 3. 精髓整个修改的精髓在于setjmp和longjmp, 这俩是一对, 长跳转. 每次程序跑到exit_program(ret)方法的时候, 本来是要结束(闪退)程序的. 但是我们直接注释掉原来的代码, 理由longjmp跳转到设置setjmp的地方去, 从而"优雅"的结束调用. 类似goto? ### 4. 使用 ``` void log_call_back(void *ptr, int level, const char *fmt, va_list vl) { static int print_prefix = 1; static int count; static char prev[1024]; char line[1024]; static int is_atty; av_log_format_line(ptr, level, fmt, vl, line, sizeof(line), &print_prefix); strcpy(prev, line); OH_LOG_ERROR(LOG_APP, "========> %{public}s", line); } void showLog(bool show) { if (show) { av_log_set_callback(log_call_back); } } int executeFFmpegCommandAPP(std::string uuid, int cmdLen, std::vector argv) { char **argv1 = vector_to_argv(argv); CallBackInfo onActionListener; // int ret = exe_ffmpeg_cmd(cmdLen, argv1, (int64_t) (&onActionListener), progressCallBack, -1); onActionListener.onFFmpegProgress = aki::JSBind::GetJSFunction(uuid + "_onFFmpegProgress"); onActionListener.onFFmpegFail = aki::JSBind::GetJSFunction(uuid + "_onFFmpegFail"); onActionListener.onFFmpegSuccess = aki::JSBind::GetJSFunction(uuid + "_onFFmpegSuccess"); Callbacks callbacks = { .onFFmpegProgress = onFFmpegProgress, .onFFmpegFail = onFFmpegFail, .onFFmpegSuccess = onFFmpegSuccess }; int ret = exe_ffmpeg_cmd(cmdLen, argv1, &callbacks); if (ret != 0) { char err[1024] = {0}; int nRet = av_strerror(ret, err, 1024); onActionListener.onFFmpegFail->Invoke(ret, err); } else { onActionListener.onFFmpegSuccess->Invoke(); } for (int i = 0; i < cmdLen; ++i) { free(argv1[i]); } return ret; } JSBIND_ADDON(ffmpegutils) JSBIND_GLOBAL() { JSBIND_PFUNCTION(executeFFmpegCommandAPP); JSBIND_FUNCTION(showLog); } ``` 在ets里面调用 ``` import { executeFFmpegCommandAPP } from '../../../cpp/types/ffmpegutils' import { logE } from '../tools' import libAddon from 'libffmpegutils.so' import { RandomUtil } from '@pura/harmony-utils'; export interface FFmpegCommandOptions { cmds: Array; onFFmpegProgress: (progress: number) => void; onFFmpegFail: (code: number, msg: string) => void; onFFmpegSuccess: () => void; } export class FFMpegUtils { static executeFFmpegCommand(options: FFmpegCommandOptions): Promise { let uuid = RandomUtil.generateUUID32() libAddon.JSBind.bindFunction(uuid + "_onFFmpegProgress", options.onFFmpegProgress) libAddon.JSBind.bindFunction(uuid + "_onFFmpegFail", options.onFFmpegFail) libAddon.JSBind.bindFunction(uuid + "_onFFmpegSuccess", options.onFFmpegSuccess) logE(options.cmds.join(' ')) return new Promise((resolve, reject) => { try { libAddon.executeFFmpegCommandAPP(uuid, options.cmds.length, options.cmds).then((code: number) => { resolve(code) }).catch((err: Error) => { reject(err) }) } catch (e) { reject(e) } }) } } ``` cmd里面直接这样用 ``` ffmpeg -i input1.mp3 output1.aac ``` 在napi_init.cpp里面, 用到了https://gitee.com/openharmony-sig/aki 的代码. 是不是很简单?