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• Ffmpeg - Convert Wav to OGG on Android (wrong metadata on some devices)

  13 décembre 2016, par Pepa Zapletal

  I have in the app Wav file and I want to convert it to the OGG format.

  I’m using ffmpeg library for it and this command :

  ffmpeg -i /storage/emulated/0/Test.wav -c:a libvorbis -q:a 5 /storage/emulated/0/Test.ogg

  But I have problem play correctly the generated OGG file on some Android devices. If I open this file in standard MediaPlayer then I get the wrong file duration, seeking is also not working very well BUT the file is played whole and correctly. This happens for example on Huawei M2 with Android 5.1 but on Samsung Galaxy S5 (with Android 5.1) the generated file is OK and playing is also OK.

  Do you have some idea where can be a problem ?

  Full output from ffmpeg :

  ffmpeg version n2.6.2 Copyright (c) 2000-2015 the FFmpeg developers
  
  built with gcc 4.9 (GCC) 20140827 (prerelease)
  
    configuration: --target-os=linux --cross-prefix=/home/chrono/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi- --arch=arm --enable-runtime-cpudetect --sysroot=/home/chrono/ffmpeg-android/toolchain-android/sysroot --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libtheora --enable-libfdk-aac --enable-nonfree --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/chrono/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/chrono/ffmpeg-android/build/armeabi-v7a --extra-cflags='-I/home/chrono/ffmpeg-android/toolchain-android/include -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all -march=armv7-a -mfpu=vfpv3-d16 -mfloat-abi=softfp' --extra-ldflags='-L/home/chrono/ffmpeg-android/toolchain-android/lib -Wl,-z,relro -Wl,-z,now -pie -Wl,--fix-cortex-a8' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=
  
    libavutil      54. 20.100 / 54. 20.100
  
    libavcodec     56. 26.100 / 56. 26.100
  
    libavformat    56. 25.101 / 56. 25.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 11.102 /  5. 11.102
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
   Input #0, wav, from '/storage/emulated/0/IAMDJ/MyLoops/mix folder/Test.wav':
  
     Metadata:
  
       encoder         : Lavf56.25.101
  
     Duration: 00:00:16.01, bitrate: 1411 kb/s
  
       Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels, s16, 1411 kb/s
  
   Output #0, ogg, to '/storage/emulated/0/Test.ogg':
  
     Metadata:
  
       encoder         : Lavf56.25.101
  
       Stream #0:0: Audio: vorbis (libvorbis), 44100 Hz, stereo, fltp
  
    Metadata:
  
        encoder         : Lavc56.26.100 libvorbis
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> vorbis (libvorbis))
  
  Press [q] to stop, [?] for help
  
  size=       4kB time=00:00:01.00 bitrate=  35.0kbits/s    
  
  size=      27kB time=00:00:02.01 bitrate= 107.8kbits/s    
  
  size=      48kB time=00:00:03.04 bitrate= 129.3kbits/s    
  
  size=      70kB time=00:00:04.06 bitrate= 140.3kbits/s    
  
  size=      91kB time=00:00:05.14 bitrate= 144.9kbits/s    
  
  size=     113kB time=00:00:06.15 bitrate= 149.7kbits/s    
  
  video:0kB audio:344kB subtitle:0kB other streams:0kB global headers:4kB muxing overhead: 1.994279%

  Edit : here is the result file : Test.ogg

  Edit 2 : Maybe there can be a problem with standard MediaPlayer but another Ogg file is played correctly.

• FFMPEG Error Handling Not Working

  23 mars 2017, par Waverunner

  I’m fairly new to batch files and trying to create a Windows script that automatically converts all files in the extensions list I provide to MP4 and log the successes and failures. The problem I’m running into is that some of the videos are failing with zero byte outputs and even though there’s two levels of error handling so the originals don’t get deleted, they aren’t working and the originals get deleted regardless if the conversions succeed or not.

  The two protections are :

  (1) FFMPEG - abort_on empty_output option

  (2) IF/ELSE loop that checks for zero-size files

  Any ideas for better error handling would be appreciated.

  :: Name:     MKV2MP4.cmd
  
  :: Purpose:  Automatically converts non-MP4 video files to MP4 either by stream copy or by reencoding.
  
  :: Revision: March 2017 - Initial version
  
  
  
  :: Variables
  
  :: %%L = List of Extensions
  
  :: %%F = Files to be converted
  
  :: %%N = New file
  
  
  
  @echo OFF
  
  CLS
  
  setlocal
  
  echo This script automatically converts non-MP4 video files to MP4 either by stream copy or by reencoding.
  
  echo.
  
  echo Changing to data directory...
  
  Z:
  
  cd Z:\Users\Todd\
  
  echo.
  
  
  
  FOR /F "delims=*" %%L IN (Z:\Logs\Extensions.txt) DO (
  
  echo Collecting %%L files...
  
  dir /b /s *.%%L > Z:\Logs\%%L.txt
  
  )
  
  echo.
  
  echo File collection complete.
  
  echo.
  
  
  
  FOR /F "delims=*" %%L in (Z:\Logs\Extensions.txt) DO (
  
  echo Working on %%L files...
  
  echo.
  
  
  
  FOR /F "delims=*" %%F in (Z:\Logs\%%L.txt) DO (
  
  echo Converting "%%F"
  
  echo.
  
  ffmpeg.exe -y -i "%%F" -abort_on empty_output -aspect 16:9 -c:v copy -c:a copy "%%~dpnF.mp4" || ffmpeg.exe -y -i "%%F" -abort_on empty_output -aspect 16:9 -c:v libx265 -c:a copy "%%~dpnF.mp4"
  
  echo.
  
  set N="%%~dpnF.mp4"
  
  
  
  IF %%~zN==0 (
  
  echo Conversion failed!  Skipping file.
  
  echo Adding log entry...
  
  echo %time% - Failed - "%%F" >> "Z:\Logs\%date:~-4,4%%date:~-10,2%%date:~-7,2% - %%L.txt"
  
  ) ELSE (
  
  echo Conversion successful!  Deleting old file.
  
  echo Deleting "%%F"
  
  del "%%F" /F
  
  echo Adding log entry...
  
  echo %time% - Successful - "%%F" >> "Z:\Logs\%date:~-4,4%%date:~-10,2%%date:~-7,2% - %%L.txt"   
  
  )
  
  
  
  echo.
  
  )
  
  
  
  echo %%L files completed.
  
  echo. Cleaning up...
  
  del %%L /F /S
  
  )
  
  
  
  echo Job completed.  Exiting..

• Approaches To Modifying Game Resource Files

  16 août 2016, par Multimedia Mike — Game Hacking

  I have been assisting The Translator in the translation of another mid-1990s adventure game. This one isn’t quite as multimedia-heavy as the last title, and the challenges are a bit different. I wanted to compose this post in order to describe my thought process and mental model in approaching this problem. Hopefully, this will help some others understand my approach since what I’m doing here often appears as magic to some of my correspondents.

  High Level Model
  At the highest level, it is valuable to understand the code and the data at play. The code is the game’s engine and the data refers to the collection of resources that comprise the game’s graphics, sound, text, and other assets.

  
  
  Simplistic high-level game engine model
  

  Ideally, we want to change the data in such a way that the original game engine adopts it as its own because it has the same format as the original data. It is very undesirable to have to modify the binary engine executable in any way.

  Modifying The Game Data Directly
  How to modify the data ? If we modify the text strings for the sake of language translation, one approach might be to search for strings within the game data files and change them directly. This model assumes that the text strings are stored in a plain, uncompressed format. Some games might store these strings in a text format which can be easily edited with any text editor. Other games will store them as binary data.
  

  In the latter situation, a game hacker can scan through data files with utilities like Unix ‘strings’ to find the resources with the desired strings. Then, use a hex editor to edit the strings directly. For example, change “Original String”…

  0098F800   00 00 00 00  00 00 00 4F  72 69 67 69  6E 61 6C 20  .......Original 
  0098F810   53 74 72 69  6E 67 00 00  00 00 00 00  00 00 00 00  String..........
  

  …to “Short String” and pad the difference in string lengths using spaces (0x20) :

  0098F800   00 00 00 00  00 00 00 53  68 6F 72 74  20 53 74 72  .......Short Str
  0098F810   69 6E 67 20  20 20 00 00  00 00 00 00  00 00 00 00  ing   ..........
  

  This has some obvious problems. First, translated strings need to be of equal our smaller length compared to the original. What if we want to encode “Much Longer String” ?

  0098F800   00 00 00 00  00 00 00 4D  75 63 68 20  4C 6F 6E 67  .......Much Long
  0098F810   65 72 20 53  74 72 00 00  00 00 00 00  00 00 00 00  er Str..........
  

  It won’t fit. The second problem pertains to character set limitations. If the font in use was only designed for ASCII, it’s going to be inadequate for expressing nearly any other language.

  So a better approach is needed.

  Understanding The Data Structures
  An alternative to the approach outlined above is to understand the game’s resources so they can be modified at a deeper level. Here’s a model to motivate this investigation :

  
  
  Model of the game resource archive format
  

  This is a very common layout for such formats : there is a file header, a sequence of resource blocks, and a trailing index which describes the locations and types of the foregoing blocks.

  What use is understanding the data structures ? In doing so, it becomes possible to write new utilities that disassemble the data into individual pieces, modify the necessary pieces, and then reassemble them into a form that the original game engine likes.

  It’s important to take a careful, experimental approach to this since mistakes can be ruthlessly difficult to debug (unless you relish the thought of debugging the control flow through an opaque DOS executable). Thus, the very first goal in all of this is to create a program that can disassemble and reassemble the resource, thus creating an identical resource file. This diagram illustrates this complex initial process :

  
  
  Rewriting the game resource file
  

  So, yeah, this is one of the most complicated “copy file” operations that I can possibly code. But it forms an important basis, since the next step is to carefully replace one piece at a time.

  
  
  Modifying a specific game resource
  

  This diagram shows a simplistic model of a resource block that contains a series of message strings. The header contains pointers to each of the strings within the block. Instead of copying this particular resource block directly to the new file, a proposed modification utility will intercept it and rewrite the entire thing, writing new strings of arbitrary length and creating an adjusted header which will correctly point to the start of each new string. Thus, translated strings can be longer than the original strings.

  Further Work
  Exploiting this same approach, we can intercept and modify other game resources including fonts, images, and anything else that might need to be translated. I will explore specific examples in a later blog post.

  Followup

  • Translating Return to Ringworld, in which I apply the ideas expressed in this post.

  The post Approaches To Modifying Game Resource Files first appeared on Breaking Eggs And Making Omelettes.