视频重新编码的ffmpeg [英] Video recoding with ffmpeg

问题描述

我问另外一个问题(http://stackoverflow.com/questions/8012494/sorry-this-video-cannot-be-played-streaming-mp4-to-android/8012874#8012874)关于Android的使用VideoView视频播放。显然，这个问题存在的原因是我的视频是带codeD的方式，作为另一个视频（MP4为512Kb关闭网页）中饰演正确使用我的code。由于影片是由我的最终用户到网站上载，我不具备视频本身的控制，但我必须在重新编写这些控制。 I C使用它们的ffmpeg 给他们带来一个标准的MP4（H.264 + AAC）格式，并将其扩展到相同的尺寸（320×240）重新$ C $

I asked in another question (http://stackoverflow.com/questions/8012494/sorry-this-video-cannot-be-played-streaming-mp4-to-android/8012874#8012874) about video playback in android using VideoView. Apparently, the problem there is due to the way my video is encoded, as another video (512Kb mp4 off the web) plays correctly using my code. As videos are uploaded by my end users to the web site, I don't have any control of the videos themselves, however I do have control over re-coding these. I re-code them using ffmpeg to bring them to a standard MP4 (H.264+AAC) format and scale them to the same size (320x240).

下面是一个视频，将无法播放的ffmpeg的信息：

Here's the ffmpeg info of a video that would not play:

sh-3.2$ ffmpeg -i video.bad.mp4
FFmpeg version SVN-r25679-snapshot, Copyright (c) 2000-2010 the FFmpeg developers
  built on Nov  5 2010 09:34:37 with gcc 4.3.2
  configuration: --prefix=/usr --enable-shared --enable-libmp3lame --enable-gpl --enable-libvorbis --enable-pthreads --enable-libfaac --enable-libxvid --enable-postproc --enable-libgsm --enable-x11grab --enable-libx264 --enable-libtheora --extra-cflags=-Wall --enable-swscale --enable-libdc1394 --enable-nonfree --disable-mmx --disable-stripping --enable-avfilter --disable-altivec --disable-armv5te --disable-armv6 --disable-vis --enable-nonfree --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-version3
  libavutil     50.32. 6 / 50.32. 6
  libavcore      0.12. 0 /  0.12. 0
  libavcodec    52.94. 3 / 52.94. 3
  libavformat   52.84. 0 / 52.84. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.56. 0 /  1.56. 0
  libswscale     0.12. 0 /  0.12. 0
  libpostproc   51. 2. 0 / 51. 2. 0
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.bad.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf52.84.0
  Duration: 00:00:45.93, start: 0.000000, bitrate: 591 kb/s
    Stream #0.0(und): Video: h264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], 535 kb/s, 15 fps, 15 tbr, 15 tbn, 30 tbc
    Stream #0.1(und): Audio: aac, 48000 Hz, stereo, s16, 51 kb/s

和这里是一个视频的ffmpeg的信息是正确播放：

And here's the ffmpeg info of a video that plays correctly:

sh-3.2$ ffmpeg -i video.mp4
FFmpeg version SVN-r25679-snapshot, Copyright (c) 2000-2010 the FFmpeg developers
  built on Nov  5 2010 09:34:37 with gcc 4.3.2
  configuration: --prefix=/usr --enable-shared --enable-libmp3lame --enable-gpl --enable-libvorbis --enable-pthreads --enable-libfaac --enable-libxvid --enable-postproc --enable-libgsm --enable-x11grab --enable-libx264 --enable-libtheora --extra-cflags=-Wall --enable-swscale --enable-libdc1394 --enable-nonfree --disable-mmx --disable-stripping --enable-avfilter --disable-altivec --disable-armv5te --disable-armv6 --disable-vis --enable-nonfree --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-version3
  libavutil     50.32. 6 / 50.32. 6
  libavcore      0.12. 0 /  0.12. 0
  libavcodec    52.94. 3 / 52.94. 3
  libavformat   52.84. 0 / 52.84. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.56. 0 /  1.56. 0
  libswscale     0.12. 0 /  0.12. 0
  libpostproc   51. 2. 0 / 51. 2. 0
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: mp41
    title           : crazytown - http://www.archive.org/details/Cartoon-Crazytown
    encoder         : Lavf51.10.0
  Duration: 00:07:50.40, start: 0.000000, bitrate: 578 kb/s
    Stream #0.0(und): Video: h264, yuv420p, 320x240, 510 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
    Stream #0.1(und): Audio: aac, 48000 Hz, stereo, s16, 63 kb/s

我这里有两个问题，其实。首先，它在我的坏的视频细节也机器人不喜欢？第二，应我的ffmpeg使用什么参数来重新code我的影片？作为present我用这个：

I have two questions here, actually. First, which of the details in my "bad" video does android not like? And, second, what parameters should I use with ffmpeg to recode my videos? As present I use this:

ffmpeg -i $input_video_file -y -s 320x240 -vcodec libx264 -vpre medium -acodec libfaac -b 510K -ar 48000 -aspect 4:3 $tmpfile.mp4
qt-faststart $tmpfile.mp4 $output_video_file.mp4

但是，这会产生一个视频，这不是在Android上播放。任何帮助是极大的AP preciated。

But this produces a video that's not playable on android. Any help is greatly appreciated.

推荐答案

首先，你的ffmpeg的版本是一岁多。很多已与去年以来的ffmpeg和H.264的提高。请尝试升级到至少ffmpeg的-0.7。

First, your version of ffmpeg is over a year old. A lot has improved with ffmpeg and H.264 since last year. Please try upgrading to at least ffmpeg-0.7.

这是一个有点难以分辨究竟哪里出了问题是因为ffmpeg的不显示传递给X264为H.264编码的所有选项。尝试（使用增加的ffmpeg输出的详细 -v 1 或 -v 2 附近的某个地方FFmpeg的命令开始）。但是，基于使用的ffmpeg到Android的跨code视频我的经验，我的猜测是，你不使用的H.264基线（见的 /H.264#Profiles\">the维基百科的文章，如果你很好奇）。尝试添加 -profile基线如果您有ffmpeg的-0.7或更高版本。

It's a little difficult to tell exactly where the problem is because ffmpeg isn't displaying all the options passed to x264 for H.264 encoding. Try increasing the verbosity of ffmpeg output (using -v 1 or -v 2 somewhere near the beginning of the ffmpeg command). But based on my experience using ffmpeg to transcode videos for Android, my guess is that you're not using the H.264 Baseline profile (see the wikipedia article on H.264 if you're curious). Try adding -profile baseline if you have ffmpeg-0.7 or later.

如果你因为某些原因或其他升级你的ffmpeg，你可以使用 -v pre基线选项指定后指定基线配置文件 -v pre中。 codeR 0 0 -bf -w -flags2 preD - 如果由于某种原因，你得到一个错误尝试使用基线preSET，你可以手动指定强制基线选项-dct8x8 的 -v pre中后，在命令行上。

If you can't upgrade your ffmpeg for some reason or another, you can specify the Baseline profile by using the -vpre baseline option after you specify -vpre medium. If for some reason you get an error trying to use the Baseline preset, you can manually force the Baseline options by specifying -coder 0 -bf 0 -flags2 -wpred-dct8x8 on the command line after the -vpre medium.

这篇关于视频重新编码的ffmpeg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！