ffmpeg从mp4文件导出的图像不清楚

Question

I am trying to take a snapshot from mp4 video. here is the code that i use through PHP:

exec("ffmpeg -ss 00:00:03 -i 1419856237575730484.mp4 -y -an -f mjpeg -vframes 1 1419856237575730484.jpg 2>&1")

the result contain the following error :

Error while decoding stream #0:0: Invalid data found when processing input (Last message repeated 37 times)

invoking the function will result an image

and the second call get another image differed from the previous one but still fuzzy and corrupted like so:

any help will be appreciated.

---

ffmpeg version N-68271-geb74839-syslint Copyright (c) 2000-2014 the FFmpeg developers
built on Dec 7 2014 04:36:06 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-11)
configuration: --prefix=/usr/local/cpffmpeg --enable-shared --enable-nonfree --enable-gpl --enable-pthreads --enable-libopencore-amrnb --enable-decoder=liba52 --enable-libopencore-amrwb --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --extra-cflags=-I/usr/local/cpffmpeg/include/ --extra-ldflags=-L/usr/local/cpffmpeg/lib --enable-version3 --extra-version=syslint
libavutil 54. 15.100 / 54. 15.100
libavcodec 56. 14.100 / 56. 14.100
libavformat 56. 15.102 / 56. 15.102
libavdevice 56. 3.100 / 56. 3.100
libavfilter 5. 2.103 / 5. 2.103
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x71fdc0] overread end of atom 'colr' by 1 bytes
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'view/media/video/1419856237575730484.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42isomavc1
creation_time : 2011-08-30 14:11:40
encoder : HandBrake 0.9.5 2011010300
title : malaf
artist : 4
comment : 3
Duration: 00:00:33.07, start: 0.000000, bitrate: 983 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 640x360, 866 kb/s, 25 fps, 25 tbr, 90k tbn, 180k tbc (default)
Metadata:
creation_time : 2011-08-30 14:11:40
encoder : JVT/AVC Coding
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
creation_time : 2011-08-30 14:11:40
[swscaler @ 0x7070c0] deprecated pixel format used, make sure you did set range correctly
Output #0, mjpeg, to 'view/media/video/1419856237575730484.jpg':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42isomavc1
comment : 3
artist : 4
title : malaf
encoder : Lavf56.15.102
Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 640x360, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc (default)
Metadata:
creation_time : 2011-08-30 14:11:40
encoder : Lavc56.14.100 mjpeg
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
Press [q] to stop, [?] for help
Error while decoding stream #0:0: Invalid data found when processing input
Last message repeated 37 times
frame= 1 fps=0.0 q=3.8 Lsize= 10kB time=00:00:00.04 bitrate=2131.6kbits/s
video:10kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000% 

Answer 1

I have discovered that this problem caused by OS permission. Re-installing FFMPEG and all required libraries and give the operated user the sufficient permission solve my problem.