我面临一个我无法解决的问题！
我尝试使用该ffmpeg工具转换视频。当我将命令粘贴到服务器终端（ssh root）时，它工作正常。但是，当我尝试使用 PHP 脚本时shell_exec，它会返回错误“打开编码器时出错 ...”。
这是我使用的命令：
ffmpeg -y -i VIDEOIN.mov -preset medium -strict -2 -c:v libx264 -b:v 1000k -pass 1 -f mp4 VIDEOOUT.mp4 </dev/null 1>logfile.txt 2>&1 &
还有我的 PHP 脚本：
$dir = 'videos/'.$uuid;
$out = $dir.'video.mp4';
$log = $dir.'transcoding_log.txt';
$preset = 'medium';
$bitrate = 1000;
$cmd = "ffmpeg -y -i ".$in." -preset ".$preset." -strict -2 -c:v libx264 -b:v ".$bitrate."k -pass 1 -f mp4 ".$out." </dev/null 1>".$log." 2>&1 &";
@file_put_contents($dir.'cmd.log', $cmd); // to debug
shell_exec($cmd);
这是在 PHP 脚本中创建的日志文件：
ffmpeg version 1.0.8 Copyright (c) 2000-2013 the FFmpeg developers
built on Sep 12 2013 11:57:09 with gcc 4.7 (Debian 4.7.2-5)
configuration: --prefix=/usr --extra-cflags='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security ' --extra-ldflags='-Wl,-z,relro' --cc='ccache cc' --enable-shared --enable-libmp3lame --enable-gpl --enable-nonfree --enable-libvorbis --enable-pthreads --enable-libfaac --enable-libxvid --enable-postproc --enable-x11grab --enable-libgsm --enable-libtheora --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libx264 --enable-libspeex --enable-nonfree --disable-stripping --enable-libvpx --enable-libschroedinger --disable-encoder=libschroedinger --enable-version3 --enable-libopenjpeg --enable-librtmp --enable-avfilter --enable-libfreetype --enable-libvo-aacenc --disable-decoder=amrnb --enable-libvo-amrwbenc --enable-libaacplus --libdir=/usr/lib/x86_64-linux-gnu --disable-vda --enable-libbluray --enable-libcdio --enable-gnutls --enable-frei0r --enable-openssl --enable-libass --enable-libopus --enable-fontconfig --enable-libfdk-aac --enable-libdc1394 --disable-altivec --dis libavutil 51. 73.101 / 51. 73.101
libavcodec 54. 59.100 / 54. 59.100
libavformat 54. 29.104 / 54. 29.104
libavdevice 54. 2.101 / 54. 2.101
libavfilter 3. 17.100 / 3. 17.100
libswscale 2. 1.101 / 2. 1.101
libswresample 0. 15.100 / 0. 15.100
libpostproc 52. 0.100 / 52. 0.100
Input #0, matroska,webm, from 'videos/18352678af96ecb5/origin.webm':
Metadata:
creation_time : 2010-05-20 08:21:12
Duration: 00:00:32.48, start: 0.000000, bitrate: 533 kb/s
Stream #0:0(eng): Video: vp8, yuv420p, 640x360, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 1k tbc (default)
Stream #0:1(eng): Audio: vorbis, 44100 Hz, mono, s16 (default)
[libx264 @ 0x19c05a0] using SAR=1/1
[libx264 @ 0x19c05a0] using cpu capabilities: MMX2 SSE2Fast SSEMisalign LZCNT
[libx264 @ 0x19c05a0] ratecontrol_init: can't open stats file
Output #0, mp4, to 'videos/18352678af96ecb5/video.mp4':
Stream #0:0(eng): Video: h264, yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=-1--1, pass 1, 90k tbn, 25 tbc (default)
Stream #0:1(eng): Audio: none, 44100 Hz, mono, s16, 128 kb/s (default)
Stream mapping:
Stream #0:0 -> #0:0 (vp8 -> libx264)
Stream #0:1 -> #0:1 (vorbis -> libfaac)
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
编辑1：
我用最新版本编译了ffmpeg，但问题仍然存在。