如何在第一个输入上运行命令行FFMPEG并接受多个管道(视频和音频)而不阻塞？

Question

我正在尝试使用FFMPEG复用h264和使用MediaCodec创建的aac,并使用FFMPEG的RTMP支持发送到youtube.我已经创建了两个管道,并且是通过WriteableByteChannels从java(android)编写的.我可以发送到一个管道就好(接受空音频),如下所示:

./ffmpeg -f lavfi -i aevalsrc=0 -i "files/camera-test.h264" -acodec aac -vcodec copy -bufsize 512k -f flv "rtmp://a.rtmp.youtube.com/live2/XXXX"

YouTube直播效果非常好(但我没有音频).使用两个管道这是我的命令:

./ffmpeg \
-i "files/camera-test.h264" \
-i "files/audio-test.aac" \
-vcodec copy \
-acodec copy \
-map 0:v:0 -map 1:a:0 \
-f flv "rtmp://a.rtmp.youtube.com/live2/XXXX""

管道是用mkfifo创建的,并从java中打开,如下所示:

pipeWriterVideo = Channels.newChannel(new FileOutputStream(outputFileVideo.toString()));

执行顺序(目前在我的测试阶段)是创建文件,启动ffmpeg(通过adb shell),然后开始记录打开通道.ffmpeg将立即打开h264流然后等待,因为它正在从管道读取第一个打开的通道(视频)将成功运行.当尝试以相同的方式打开音频时,它会失败,因为ffmpeg实际上还没有开始从管道中读取.我可以打开第二个终端窗口并播放音频文件,我的应用程序吐出我希望编码的aac,但ffmpeg失败,通常只是坐在那里等待.这是详细输出:

ffmpeg version N-78385-g855d9d2 Copyright (c) 2000-2016 the FFmpeg
developers
  built with gcc 4.8 (GCC)
  configuration: --prefix=/home/dev/svn/android-ffmpeg-with-rtmp/src/ffmpeg/android/arm 
    --enable-shared --disable-static --disable-doc --disable-ffplay 
    --disable-ffprobe --disable-ffserver --disable-symver 
    --cross-prefix=/home/dev/dev/android-ndk-r10e/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/arm-linux-androideabi- 
    --target-os=linux --arch=arm --enable-cross-compile 
    --enable-librtmp --enable-pic --enable-decoder=h264 
    --sysroot=/home/dev/dev/android-ndk-r10e/platforms/android-19/arch-arm 
    --extra-cflags='-Os -fpic -marm' 
    --extra-ldflags='-L/home/dev/svn/android-ffmpeg-with-rtmp/src/openssl-android/libs/armeabi ' 
    --extra-ldexeflags=-pie --pkg-config=/usr/bin/pkg-config
  libavutil      55. 17.100 / 55. 17.100
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
 matched as AVOption 'debug' with argument 'verbose'.
Trailing options were found on the commandline.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option async (audio sync method) with argument 1.
Successfully parsed a group of options.
Parsing a group of options: input file files/camera-test.h264.
Successfully parsed a group of options.
Opening an input file: files/camera-test.h264.
[file @ 0xb503b100] Setting default whitelist 'file'

我想如果我能让ffmpeg开始听两个管道,剩下的就可以了!

谢谢你的时间.

编辑:我通过解耦音频管道连接和编码取得了进展,但现在一旦视频流传递它就会出现音频错误.我启动了一个单独的线程来为音频创建WriteableByteChannel,它永远不会传递FileOutputStream创建.

matched as AVOption 'debug' with argument 'verbose'.
Trailing options were found on the commandline.
Finished splitting the commandline.
Parsing a group of options: global .
Successfully parsed a group of options.
Parsing a group of options: input file files/camera-test.h264.
Successfully parsed a group of options.
Opening an input file: files/camera-test.h264.
[file @ 0xb503b100] Setting default whitelist 'file'
[h264 @ 0xb503c400] Format h264 probed with size=2048 and score=51
[h264 @ 0xb503c400] Before avformat_find_stream_info() pos: 0 bytes read:15719 seeks:0
[h264 @ 0xb5027400] Current profile doesn't provide more RBSP data in PPS, skipping
[h264 @ 0xb503c400] max_analyze_duration 5000000 reached at 5000000 microseconds st:0
[h264 @ 0xb503c400] After avformat_find_stream_info() pos: 545242 bytes read:546928 seeks:0 frames:127
Input #0, h264, from 'files/camera-test.h264':
  Duration: N/A, bitrate: N/A
    Stream #0:0, 127, 1/1200000: Video: h264 (Baseline), 1 reference frame, yuv420p(left), 854x480 (864x480), 1/50, 25 fps, 25 tbr, 1200k tbn, 50 tbc
Successfully opened the file.
Parsing a group of options: input file files/audio-test.aac.
Applying option vcodec (force video codec ('copy' to copy stream)) with argument copy.
Successfully parsed a group of options.
Opening an input file: files/audio-test.aac.
Unknown decoder 'copy'
[AVIOContext @ 0xb5054020] Statistics: 546928 bytes read, 0 seeks

这是我尝试打开音频管道的地方.

new Thread(){
     public void run(){
          Log.d("Audio", "pre thread");
          FileOutputStream fs = null;
          try {
               fs = new FileOutputStream("/data/data/android.com.android.grafika/files/audio-test.aac");
          } catch (FileNotFoundException e) {
               e.printStackTrace();
          }
          Log.d("Audio", "made fileoutputstream");  //never hits here
          mVideoEncoder.pipeWriterAudio = Channels.newChannel(fs);
          Log.d("Audio", "made it past opening audio pipe");
     }
}.start();

谢谢.

Answer 1

您的解释不是很清楚，我可以看到您试图准确解释您在做什么，但这不起作用。

第一：你能描述一下实际问题吗？我必须读到你的帖子的一半，变成一个 8 行段落，看起来你在建议 ffmpeg ishanging。这是问题所在吗？你确实想明确说明这一点。

其次：如何将数据传送到 FIFO 中？这很重要。您的帖子完全不清楚，您似乎建议 ffmpeg 读取整个视频文件，然后移动到音频。那是对的吗？或者两个流同时馈送到 ffmpeg？

最后：如果 ffmpeg 挂起，很可能是因为您的输入管道之一被阻塞（您将数据推送到 FIFO-1 并且缓冲区已满，但 ffmpeg 需要来自 FIFO-2 的数据并且缓冲区为空）。两个 FIFO 都需要始终独立地填充数据。