我目前在CentOS 6.3上使用FFMPEG v1.1。
我将FFMPEG配置为：
./configure --arch=x86_64 --enable-libmp3lame --enable-librtmp --enable-libtheora --enable-libvorbis --enable-libx264 --enable-pthreads --enable-gpl --enable-runtime-cpudetect
当我运行一个简单的命令将实时输入录制到MP4时：
ffmpeg -f video4linux2 -s 640x480 -i /dev/video0 /home/irdb/Desktop/test.mp4
我什么都没得到，只是一个灰色的屏幕边缘有一些文物。但是，当我运行与.MPG相同的命令时，它会很好。但是我需要MP4格式。
另一方面，我正在运行通过yum安装的x264-0.120
我的问题是，我编译ffmpeg的方式有问题吗？或者它可能是别的什么？
修改
按要求从示例输出：
# ffmpeg -f video4linux2 -s 640x480 -t 5 -i /dev/video0 -strict 2 /home/irdb/Desktop/test.mp4
ffmpeg version N-50546-g1f5b5b8 Copyright (c) 2000-2013 the FFmpeg developers
built on Mar 7 2013 00:17:44 with gcc 4.4.6 (GCC) 20120305 (Red Hat 4.4.6-4)
configuration: --enable-libmp3lame --enable-librtmp --enable-libtheora --enable- libvorbis --enable-libx264 --enable-pthreads --enable-gpl --enable-runtime-cpudetect
libavutil 52. 18.100 / 52. 18.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 54. 3.103 / 54. 3.103
libavfilter 3. 42.103 / 3. 42.103
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[video4linux2,v4l2 @ 0x3025120] Estimating duration from bitrate, this may be inaccurate
Input #0, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 128.640356, bitrate: 147456 kb/s
Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
[libx264 @ 0x3026f80] using cpu capabilities: MMX2 SSE2Fast SSEMisalign LZCNT
[libx264 @ 0x3026f80] profile High 4:2:2, level 3.0, 4:2:2 8-bit
[libx264 @ 0x3026f80] 264 - core 130 r2274 c832fe9 - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to '/home/irdb/Desktop/test.mp4':
Metadata:
encoder : Lavf54.63.104
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv422p, 640x480, q=-1--1, 15360 tbn, 30 tbc
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo -> libx264)
Press [q] to stop, [?] for help
frame= 32 fps=0.0 q=0.0 size= 0kB time=00:00:00.00 bitrate=N/A dup=21 drframe= 46 fps= 46 q=0.0 size= 0kB time=00:00:00.00 bitrate=N/A dup=28 drframe= 62 fps= 41 q=29.0 size= 71kB time=00:00:00.33 bitrate=1735.2kbits/frame= 76 fps= 38 q=29.0 size= 169kB time=00:00:00.80 bitrate=1731.2kbits/frame= 93 fps= 37 q=29.0 size= 311kB time=00:00:01.36 bitrate=1862.3kbits/frame= 107 fps= 35 q=29.0 size= 423kB time=00:00:01.83 bitrate=1891.0kbits/frame= 123 fps= 35 q=29.0 size= 537kB time=00:00:02.36 bitrate=1860.2kbits/frame= 139 fps= 34 q=29.0 size= 664kB time=00:00:02.90 bitrate=1876.0kbits/frame= 150 fps= 29 q=-1.0 Lsize= 1174kB time=00:00:04.93 bitrate=1948.7kbits/s dup=81 drop=0
video:1172kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.133409%
[libx264 @ 0x3026f80] frame I:2 Avg QP:23.22 size: 28460
[libx264 @ 0x3026f80] frame P:136 Avg QP:24.45 size: 8397
[libx264 @ 0x3026f80] frame B:12 Avg QP:26.18 size: 42
[libx264 @ 0x3026f80] consecutive B-frames: 88.0% 4.0% 0.0% 8.0%
[libx264 @ 0x3026f80] mb I I16..4: 47.1% 28.8% 24.1%
[libx264 @ 0x3026f80] mb P I16..4: 4.3% 1.9% 1.2% P16..4: 29.0% 11.4% 9.2% 0.0% 0.0% skip:43.0%
[libx264 @ 0x3026f80] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 1.5% 0.0% 0.0% direct: 0.0% skip:98.5% L0:16.5% L1:83.5% BI: 0.0%
[libx264 @ 0x3026f80] 8x8 transform intra:26.4% inter:30.7%
[libx264 @ 0x3026f80] coded y,uvDC,uvAC intra: 85.2% 95.6% 83.5% inter: 10.9% 38.6% 24.0%
[libx264 @ 0x3026f80] i16 v,h,dc,p: 33% 19% 40% 8%
[libx264 @ 0x3026f80] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 6% 12% 55% 5% 3% 4% 4% 3% 8%
[libx264 @ 0x3026f80] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 15% 9% 63% 3% 2% 2% 2% 2% 2%
[libx264 @ 0x3026f80] i8c dc,h,v,p: 66% 11% 14% 9%
[libx264 @ 0x3026f80] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x3026f80] ref P L0: 56.6% 7.5% 8.1% 27.8%
[libx264 @ 0x3026f80] ref B L0: 83.3% 16.7%
[libx264 @ 0x3026f80] ref B L1: 90.7% 9.3%
[libx264 @ 0x3026f80] kb/s:1918.95
答案 0 :(得分：6)
您用于显示视频的播放器可能不支持您的输出视频的像素格式。如果您观察输出日志，则可以看到yuv422p被选为格式。这是平面格式的4：2：2 subsampled chroma。
选择-pix_fmt yuv420p（4：2：0子采样）应该会为您提供可在任何地方查看的H.264编码视频。
ffmpeg -f video4linux2 -s 640x480 -i /dev/video0 \
-c:v libx264 -pix_fmt yuv420p /home/irdb/Desktop/test.mp4
我在这里明确设置了视频编解码器。只是一个良好的习惯，以便在FFmpeg默认为格式的另一个编码器时不要感到惊讶。例如，选择MPEG输出格式使FFmpeg选择另一个默认编码器MPEG-1（mpeg1video），它再次使用4：2：0子采样。