Recherche avancée

Sur d’autres sites (6477)

• Write unencoded ffmpeg packets to a file

  24 janvier 2017, par user92238

  I’m using ffmpeg to receive packets (AVPacket) from an RTSP server.

  Rather than decode the packets, I want to write them directly to an MP4 file that can be later opened by a media player. It is important that my application does not incur the overhead of decoding and re-encoding the packets.

  I tried simply writing the contents of the AVPacket data field out to a file, but the result is not playable.

  I suspect that I need to put additional information at the beginning of the file and/or between the packets to satisfy the MP4 file format. Is there an easy way to do this using ffmpeg functions, or is it something I’ll need to code by hand ? Where can I find the file format ?

  Thanks,
  Frank

• Building FFMPEG library for iOS5.1 ARMv7 Processor

  26 octobre 2012, par Jimmy

  I cleaned up my question a little bit, when I wrote it the first time I was flustered. Now I can be more clear after taking a small break.

  I'm trying to use the FFMPEG library in an XCode 4.5.1 project. And I'm trying to build it for ARMv7. What I'm looking for is the exact process, and some explanation. I understand that this is not a well documented problem. But I know that other pople have had the same problem as me.

  What I have been able to do.

  I have been able to build the library for xCode. here Is what I have been able to do step by step.

  1) I have been able to clone ffmpeg. For beginners this will get you started by creating a directory with the ffmpeg source. (Kudos to the guys who wrote it)

  git clone git ://source.ffmpeg.org/ffmpeg.git ffmpeg

  2) I have been able to write a config file that doesn't have any errors. We will go back to this part later. This is the command I attach to ./configure

  ./configure
  —disable-doc
  —disable-ffmpeg
  —disable-ffplay
  —disable-ffserver
  —enable-cross-compile
  —arch=arm
  —target-os=darwin
  —cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2

  —as='gas-preprocessor/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2'

  —sysroot=/applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk

  —cpu=cortex-a8
  —extra-ldflags='-arch=armv7 -isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk'
  —enable-pic —disable-bzlib —disable-gpl —disable-shared —enable-static —disable-mmx —disable-debug —disable-neon —extra-cflags='-pipe -Os -gdwarf-2 -isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
  -m$thumb_opt :-no-thumb -mthumb-interwork'

  These are some things to note.

  • I had to download ( https://github.com/yuvi/gas-preprocessor ) copy the file gas-preprocessor.pl at /usr/local/bin. Set permissions to read write (777)
  • Make sure I'm using the right GCC compiler : /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2
  • Make sure I'm using the right SDK : /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
  • —extra-cflags="-arch armv7" causes : error : unrecognized command line option “-arch”

  Here in lies the problem.

  When I include the library and the declaration. Everything works fine ! (You will want to make sure your library paths in xcode are properly written if it can't find the library. There are plenty of people with this problem, stackover flow has a wealth of knowledge here)

  But when I started to write the encoder. I received this warning, and countless errors.

  ignoring file /Users/Jimmy/Development/source.ffmpeg/Library/libavutil.a, file was built for archive which is not the architecture being linked (armv7s) : /Users/Jimmy/Development/source.ffmpeg/Library/libavutil.a

  That means that I didn't build for ARMv7 and that -arch configuration I took out is actually essential.

  What I'm looking for is someone whose done it before, to walk all of us through the process of building FFMPEG for iOS5.1 and ARMv7 and the majority of things to look out for. If no one comes forth, in time I'll answer my own question and hopefully help out others who are struggling too.

• How to build ffmbc with static libraries on Mac

  27 janvier 2013, par Brainware

  I can build ffmbc (similar to ffmpeg) and it runs fine from the terminal. But, when I try to run it from MAMP it loads different dynamic libraries and crashes. What I would really like to do is have ffmbc load the same libraries each time no matter how it's run. Static libraries should do the trick. Another option is to create a Mac app (ffmbc.app) and use package contents. But, I don't know how to do either of these things. An XCode project would probably be best but I can't find one for ffmbc.

  I see people spending days to get things to build on their machines. I don't understand why the linux community makes this so difficult and so fragile. I've been writing apps for over 25 years so I guess I'm not as interested in jumping through hoops like I use to be. ;-)

  Suggestions or advice most appreciated.