FFMPEG x264 MP4 编码全灰色 [英] FFMPEG x264 MP4 Encoding all grey
问题描述
我目前在 CentOS 6.3 上使用 FFMPEG v1.1.
I am currently using FFMPEG v1.1 on CentOS 6.3.
我配置了 FFMPEG:
I configured FFMPEG with:
./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:
when I run a simple command to record live input to MP4 by:
ffmpeg -f video4linux2 -s 640x480 -i /dev/video0 /home/irdb/Desktop/test.mp4
我什么也没得到，只是一个灰色的屏幕，边缘有一些伪影.但是，当我运行与 .MPG 相同的命令时，结果很好.但是，我需要 MP4 格式.
I get nothing, just a grey screen with some artifacts around the edges. However when I run the same command as .MPG it comes out fine. I need it in MP4 format however.
顺便说一句，我正在运行通过 yum 安装的 x264-0.120
On a side note I am running x264-0.120 installed through yum
我的问题是，我编译ffmpeg的方式有问题吗?或者可能是别的什么?
My question is, is there a problem with the way I compiled ffmpeg? Or is it possibly something else?
根据要求从示例中输出:
Output from example as requested:
# 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
推荐答案
您用来显示视频的播放器可能不支持您输出视频的像素格式.如果您观察输出日志，您可以看到 yuv422p 被选为格式.这是平面格式的 4:2:2 子采样色度.
Your output video's pixel format is probably unsupported in the player you're using to show the video. If you observe your output logs, you can see yuv422p being chosen as the format. That's a 4:2:2 subsampled chroma in a planar format.
选择 -pix_fmt yuv420p(4:2:0 子采样)应该会给你一个 H.264 编码的视频，可以在任何地方观看.
Choosing -pix_fmt yuv420p (4:2:0 subsampling) should give you an H.264-encoded video that can be viewed everywhere.
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.养成一个好习惯，以免在 FFmpeg 默认使用其他编码器的格式时感到惊讶.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.
I explicitly set the video codec here. Just a good habit to develop so as not to be surprised when FFmpeg defaults to another encoder for a format. For example, choosing an MPEG output format made FFmpeg choose another default encoder, MPEG-1 (mpeg1video), which uses 4:2:0 subsampling again.
这篇关于FFMPEG x264 MP4 编码全灰色的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
