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• Compile ffmpeg with librtmp

  22 avril 2013, par HighFlyingFantasy

  When compiling ffmpeg for OSX, I can simply use the :

  ./configure --enable-librtmp --enable-gpl

  command and get a build that can I/O with an rtmp stream.

  If I attempt to compile for iOS using :

  ./configure \
  
  --disable-ffmpeg \
  
  --disable-ffplay \
  
  --disable-ffprobe \
  
  --disable-ffserver \
  
  --disable-mmx \
  
  --enable-gpl \
  
  --enable-shared \
  
  --enable-librtmp \
  
  --enable-avresample \
  
  --enable-cross-compile \
  
  --enable-pic \
  
  --sysroot="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs /iPhoneOS6.1.sdk" \
  
  --target-os=darwin \
  
  --cc="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2" \
  
  --extra-cflags="-arch armv7s -mfpu=neon -miphoneos-version-min=6.1" \
  
  --extra-ldflags="-arch armv7s -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk -miphoneos-version-min=6.1" \
  
  --arch=arm \
  
  --cpu=cortex-a9 \
  
  --prefix=compiled/armv7s 

  it errors out saying ERROR: librtmp cannot be found. Specifically :

      /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2 -arch armv7s -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk -miphoneos-version-min=6.1 --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.1.sdk -Wl,-dynamic,-search_paths_first -I/usr/local/include -L/usr/local/lib -o /var/folders/4m/8hcrycqx777_ksz6d32nrn_m0000gp/T//ffconf.b2zp97z8 /var/folders/4m/8hcrycqx777_ksz6d32nrn_m0000gp/T//ffconf.VhdlpSe1.o -lrtmp -lz -lssl -lcrypto -lm -lbz2 -lz
  
  ld: warning: ld: warning: ignoring file /usr/local/lib/librtmp.dylib, file was built for unsupported file format ( 0xcf 0xfa 0xed 0xfe 0x 7 0x 0 0x 0 0x 1 0x 3 0x 0 0x 0 0x 0 0x 6 0x 0 0x 0 0x 0 ) which is not the architecture being linked (armv7s): /usr/local/lib/librtmp.dylibignoring file /usr/local/lib/libz.a, file was built for archive which is not the architecture being linked (armv7s): /usr/local/lib/libz.a
  
  
  
  Undefined symbols for architecture armv7s:
  
    "_RTMP_Socket", referenced from:
  
        _check_RTMP_Socket in ffconf.VhdlpSe1.o
  
       (maybe you meant: _check_RTMP_Socket)
  
  ld: symbol(s) not found for architecture armv7s
  
  collect2: ld returned 1 exit status
  
  ERROR: librtmp not found

  I have already compiled openssl for ios using ios-openssl found on github and librtmp through rtmpdump

• Revision 200 : Added support for the —quiet option. Added audio tags checking. Fixed handling

  7 juin 2010, par marc.noirot

  Changed Paths :
   Modify /trunk/src/check.c

  
   Modify /trunk/src/flv.c

  
   Modify /trunk/src/flv.h

  
  
  Added support for the —quiet option.
  Added audio tags checking.
  Fixed handling of empty body tags in flv functions.
  Fixed check exit code in case the file has errors.

• Brute Force Dimensional Analysis

  15 juillet 2010, par Multimedia Mike — Game Hacking, Python

  I was poking at the data files of a really bad (is there any other kind ?) interactive movie video game known simply by one letter : D. The Sega Saturn version of the game is comprised primarily of Sega FILM/CPK files, about which I wrote the book. The second most prolific file type bears the extension ’.dg2’. Cursory examination of sample files revealed an apparently headerless format. Many of the video files are 288x144 in resolution. Multiplying that width by that height and then doubling it (as in, 2 bytes/pixel) yields 82944, which happens to be the size of a number of these DG2 files. Now, if only I had a tool that could take a suspected raw RGB file and convert it to a more standard image format.

  Here’s the FFmpeg conversion recipe I used :

   ffmpeg -f rawvideo -pix_fmt rgb555 -s 288x144 -i raw_file -y output.png
  

  So that covers the files that are suspected to be 288x144 in dimension. But what about other file sizes ? My brute force approach was to try all possible dimensions that would yield a particular file size. The Python code for performing this operation is listed at the end of this post.

  It’s interesting to view the progression as the script compresses to different sizes :

  
  
  

  That ’D’ is supposed to be red. So right away, we see that rgb555(le) is not the correct input format. Annoyingly, FFmpeg cannot handle rgb555be as a raw input format. But this little project worked well enough as a proof of concept.

  If you want to toy around with these files (and I know you do), I have uploaded a selection at : http://multimedia.cx/dg2/.

  Here is my quick Python script for converting one of these files to every acceptable resolution.

  work-out-resolution.py :
  

  PLAIN TEXT

  PYTHON :

  1. # !/usr/bin/python
  2.  
  3. import commands
  4. import math
  5. import os
  6. import sys
  7.  
  8. FFMPEG = "/path/to/ffmpeg"
  9.  
  10. def convert_file(width, height, filename) :
  11.  outfile = "%s-%dx%d.png" % (filename, width, height)
  12.  command = "%s -f rawvideo -pix_fmt rgb555 -s %dx%d -i %s -y %s" % (FFMPEG, width, height, filename, outfile)
  13.  commands.getstatusoutput(command)
  14.  
  15. if len(sys.argv) <2 :
  16.  print "USAGE : work-out-resolution.py <file>"
  17.  sys.exit(1)
  18.  
  19. filename = sys.argv[1]
  20. if not os.path.exists(filename) :
  21.  print filename + " does not exist"
  22.  sys.exit(1)
  23.  
  24. filesize = os.path.getsize(filename) / 2
  25.  
  26. limit = int(math.sqrt(filesize)) + 1
  27. for i in xrange(1, limit) :
  28.  if filesize % i == 0 and filesize & 1 == 0 :
  29.   convert_file(i, filesize / i, filename)
  30.   convert_file(filesize / i, i, filename)