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當(dāng)我準備使用ffmpeg截取視頻幀時出現(xiàn)了如題錯誤提示。

使用命令如下：

ffmpeg -ss 15.683 -i /storage/emulated/0/test.mp4 -y -f image2 -t 0.001 /storage/emulated/0/0.jpg

為了便于理解梗夸，在說解決方法之前层玲，先解釋一下這個命令的各參數(shù)用處：

-ss 15.683 ：將視頻指向 15.683 秒，也就是從 15.683 秒開始

-i /storage/emulated/0/test.mp4 ：輸入 test.mp4 文件

-y：強制覆蓋文件（防止因為重名出錯）

-f image2：文件格式

-t 0.001 ：持續(xù)時間（在本例中就相當(dāng)于只取原視頻的第 15.683秒-15.684秒）

/storage/emulated/0/0.jpg：輸出文件路徑

輸入該命令會概率性的輸出空文件反症，并提示以下錯誤：

ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers

built with gcc 4.8 (GCC)

? ? ? configuration: --target-os=linux --cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi- --arch=arm --cpu=cortex-a8 --enable-runtime-cpudetect --sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-fontconfig --enable-pthreads --disable-debug --disable-ffserver --enable-version3 --enable-hardcoded-tables --disable-ffplay --disable-ffprobe --enable-gpl --enable-yasm --disable-doc --disable-shared --enable-static --pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/vagrant/SourceCode/ffmpeg-android/build/armeabi-v7a --extra-cflags='-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all' --extra-ldflags='-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib -Wl,-z,relro -Wl,-z,now -pie' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=

? ? ? libavutil? ? ? 55. 17.103 / 55. 17.103

? ? ? 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

? ? ? libpostproc? ? 54.? 0.100 / 54.? 0.100

? ? Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/storage/emulated/0/DCIM/SportsCamera/YDTL0254.mp4':

? ? ? Metadata:

? ? ? ? major_brand? ? : avc1

? ? ? ? minor_version? : 0

? ? ? ? compatible_brands: avc1isom

? ? ? ? creation_time? : 2018-11-21 06:19:31

? ? ? Duration: 00:00:17.98, start: 0.000000, bitrate: 60305 kb/s

? ? ? ? Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc, bt709), 3840x2160, 60301 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)

? ? ? ? Metadata:

? ? ? ? ? creation_time? : 2018-11-21 06:19:31

? ? ? ? ? handler_name? ? :? XiaoYi AVC?

? ? ? ? ? encoder? ? ? ? : Ambarella AVC encoder

? ? Output #0, image2, to '/storage/emulated/0/Android/data/com.equationl.videoshotpro/cache/3.jpg':

? ? ? Metadata:

? ? ? ? major_brand? ? : avc1

? ? ? ? minor_version? : 0

? ? ? ? compatible_brands: avc1isom

? ? ? ? encoder? ? ? ? : Lavf57.25.100

? ? ? ? Stream #0:0(eng): Video: mjpeg, yuvj420p(pc), 3840x2160, q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc (default)

? ? ? ? Metadata:

? ? ? ? ? creation_time? : 2018-11-21 06:19:31

? ? ? ? ? handler_name? ? :? XiaoYi AVC?

? ? ? ? ? encoder? ? ? ? : Lavc57.24.102 mjpeg

? ? ? ? Side data:

? ? ? ? ? unknown side data type 10 (24 bytes)

? ? Stream mapping:

? ? ? Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))

? ? Press [q] to stop, [?] for help

? ? frame=? ? 0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=? 0x? ?

? ? video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

? ? Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

搜索了一圈沒有發(fā)現(xiàn)類似的問題辛块，而且令人費解的是，該問題是概率性出現(xiàn)惰帽，并且出現(xiàn)時間幾乎找不到任何規(guī)律憨降。

雖然網(wǎng)上沒有發(fā)現(xiàn)有類似的問題，但是我卻發(fā)現(xiàn)我的寫法似乎有點奇怪：

一般來說该酗，使用 ffmpeg 會首先使用 -i?參數(shù)輸入文件再使用 -ss?參數(shù)將其指向需要的位置授药，但是這樣寫的話效率比較低（具體原因網(wǎng)上有很多解釋，我就不多說了）呜魄，所以我先使用 -ss?移動指針再 -i?輸入文件悔叽，問題似乎就出在這了，我看見網(wǎng)上幾乎所有人的寫法都是 -ss?參數(shù)?和 -t?參數(shù)連在一起使用的爵嗅，而我不知道為什么娇澎，居然把他們分開了...

所以當(dāng)我將其放在一起后，就正常了：

ffmpeg -ss 15.683 -t 0.001 -i /storage/emulated/0/test.mp4 -y -f image2 /storage/emulated/0/0.jpg

所以說睹晒，解決方案就是按照錯誤提示所說的趟庄，檢查一下你的 -ss -t -frames?參數(shù)如果你有使用這些參數(shù)的話括细。

不過令我費解的是為什么 -ss?和 -t?分開后會概率性的出現(xiàn)輸出空文件而不是直接100%輸出錯誤呢？希望有大佬能不吝指教戚啥。

下面給大家附上幾個ffmpeg常見錯誤和解決方法吧奋单，讓大家能少踩坑。（下文轉(zhuǎn)自：https://trac.ffmpeg.org/wiki/Errors）

Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument

When encountered this message is usually the last line in the console output. By itself is not very informative, but it is always accompanied by a more specific message that explains the actual issue, so scroll up for the actual error.

Invalid input file index: 2

The?-map?option is used to choose what inputs you want when default stream selection behavior does not fit your needs. This message can occur when the?-map?option is used to reference an input that does not exist. For example, if you have two inputs, but you're tyring to map a non-existing third input with?-map 2?(note that?ffmpeg?starts counting from?0) then this error will appear.

Properly define your?-map?file index values. See the-map option documentationandFFmpeg Wiki: Mapfor more examples.

Stream map '0:a:0' matches no streams

Similar to the above error, but instead of an incorrect file index there is an incorrect stream index. For example, if the first input contains four video streams, but you use?-map 0:v:4, then you are referencing a non-existing video stream (note that?ffmpeg?starts counting from?0).

Properly define your?-map?stream index values. See the-map option documentationandFFmpeg Wiki: Mapfor more examples. Alternatively, add a trailing???to your map option, such as?-map 0:v:4?, to make the map optional.

Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

The?-ss?option allows you to skip to a certain point. This message is often seen when the?-ss?option value is greater than the duration of the input. For example, if?-ss 30?is used for a 15 second input you may see this message.

Make sure your?-ss,?-t,?-to, and/or?-frames?value does not exceed the input duration.

Unknown encoder 'foo'

Your?ffmpeg?build does not support the encoder you are trying to use.

If it is an external encoder, usually named with the "lib-" prefix, then the build must be compiled to support it. See?ffmpeg -encoders?for a list of encoders supported by your particular build.

You may be using an old, unsupoprted build. Development is very active, so it is recommended to use builds from the current git master branch. See theFFmpeg Downloadpage for options.

The issue could be a simple typo so check the spelling of the encoder name.

Use a current?ffmpeg?build. You may need tocompileit to support your desired encoder. Alternatively, you may simplydownloada static build of?ffmpeg–these builds usually support the most common encoders.

Trailing options were found on the commandline

This message is often overlooked by users and is caused by improper option placement. Placement of options matters, and trailing options are often ignored. Placement is as follows:

ffmpeg [global options] [input options] -i input [output options] output

Thedocumentationwill often specify if an option is global, input, and/or output.

Place your options in the correct location. Options before?-i?will be applied to the input, and options before the output name will be applied to the output. Options after the last output may be ignored.

No pixel format specified, yuv444p for H.264 encoding chosen.

Use -pix_fmt yuv420p for compatibility with outdated media players.

Your input and output may vary in supported pixel formats.?ffmpeg?will attempt to choose the "best" supported pixel format for your encoder. For libx264 it may use a pixel format that is not decodable by many non-FFmpeg based media players.

Adding?-pix_fmt yuv420p?or?-vf format=yuv420p?will ensure compatibility with dumb players.

[image2 @ 0x2e43320] Could not open file : images/output.png.tmp

av_interleaved_write_frame(): Input/output error

In this example the output was?images/output.png, but the?images?directory did not exist.

Check that your directory exists and/or that the permissions are correct.

[image2 @ 0x3841320] Could not get frame filename number 2 from pattern 'output.png' (either set updatefirst or use a pattern like %03d within the filename pattern)

av_interleaved_write_frame(): Invalid argument

This usually occurs because the output name is incorrect or some option was omitted.

If outputting a single image you need to include?-frames:v 1.

If outputting a series of images you need to use the proper naming pattern as described in the image muxer documentation. For example,?output_%03d.png?will make a series named?output_001.png,?output_002.png,?output_003.png, etc.

If outputting a single image that is continuously overwritten with new images, add?-update 1.

[mp4 @ 0x563cd3fa4700] Could not find tag for codec foo in stream #0, codec not currently supported in container

As the message says, the particular codec is not supported in your output container format.

Change the codec and/or output container format.

Streamcopy requested for output stream 0:0, which is fed from a complex filtergraph. Filtering and streamcopy cannot be used together

You can'tstream copy(-c copy,?-codec copy, etc) an output from a filter.

Remove this option or change?copy?to your desired encoder.