Java调用FFmpeg在Linux环境下无响应无报错问题排查

问题现象 #

开发的播客下载器需调用FFmpeg处理下载后的音频文件，Windows环境运行正常，但Linux环境下调用FFmpeg时出现异常：

• process.waitFor()返回值为-1
• Java日志无报错信息，ffmpeg.log为空
• 未生成目标处理文件
• 手动在Linux命令行执行相同命令可正常完成处理

已排除FFmpeg权限问题（权限为rwxr-xr-x），且验证FFmpeg路径可被正确定位（修改路径为大写时触发"找不到文件"错误）。

问题代码与错误参数 #

Java调用代码 #

ProcessBuilder processBuilder = new ProcessBuilder( commands );
processBuilder.redirectErrorStream( true );
//  Added the next line to see if I could log an error from ffmpeg
processBuilder.redirectOutput( ProcessBuilder.Redirect.appendTo( new File( "./ffmpeg.log" ) ) );

Process process = processBuilder.start();
BufferedReader bufferedOutputReader = new BufferedReader( new InputStreamReader( process.getInputStream() ) );
do {
    outputString = bufferedOutputReader.readLine();
    if ( outputString != null ) {
        LOGGER.trace( outputString );
    }
} while ( outputString != null );
results = process.waitFor();
LOGGER.debug( "Exit value: " + results );

错误的命令参数（含多余双引号） #

2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: /bin/ffmpeg 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -y 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -i 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: "/home/todd/aggregator/incoming/Downrange Radio/Downrange_Radio_2023-02-15_The_Avidity_PD-10_Delivers_.mp3" 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -ac 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: 1 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -af 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: "atempo=1.4,volume=1.4" 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: "/home/todd/aggregator/processed/Downrange Radio/Downrange_Radio_2023-02-15_The_Avidity_PD-10_Delivers_.mp3"

根因分析 #

命令行中使用双引号是为了告诉shell：带空格的字符串是一个完整的参数，但ProcessBuilder是直接将参数数组传递给目标进程，不需要依赖shell解析。手动给参数添加双引号后，这些引号会被当成参数内容的一部分，导致FFmpeg无法识别带引号的路径和滤镜参数，进而无法正常启动处理流程。

解决方案 #

移除所有参数中手动添加的双引号，直接传递原始路径和参数值：

修正后的参数示例 #

2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: /bin/ffmpeg 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -y 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -i 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: /home/todd/aggregator/incoming/Downrange Radio/Downrange_Radio_2023-02-15_The_Avidity_PD-10_Delivers_.mp3 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -ac 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: 1 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: -af 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: atempo=1.4,volume=1.4 
2023-10-25 16:21:52,452 224257 [pool-1-thread-4] DEBUG org.sperbolink.utils.CodecUtils - command string: /home/todd/aggregator/processed/Downrange Radio/Downrange_Radio_2023-02-15_The_Avidity_PD-10_Delivers_.mp3

ProcessBuilder会自动将带空格的路径作为单个参数传递给FFmpeg，效果与命令行手动执行一致。

内容的提问来源于stack exchange，提问作者Todd