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• Adding A New System To The Game Music Website

  1er août 2012, par Multimedia Mike — General

  At first, I was planning to just make a little website where users could install a Chrome browser extension and play music from old 8-bit NES games. But, like many software projects, the goal sort of ballooned. I created a website where users can easily play old video game music. It doesn’t cover too many systems yet, but I have had individual requests to add just about every system you can think of.

  The craziest part is that I know it’s possible to represent most of the systems. Eventually, it would be great to reach Chipamp parity (a combination plugin for Winamp that packages together plugins for many of these chiptunes). But there is a process to all of this. I have taken to defining a number of phases that are required to get a new system covered.

  Phase 0 informally involves marveling at the obscurity of some of the console systems for which chiptune collections have evolved. WonderSwan ? Sharp X68000 ? PC-88 ? I may be viewing this through a terribly Ameri-centric lens. I’ve at least heard of the ZX Spectrum and the Amstrad CPC even if I’ve never seen either.

  No matter. The goal is to get all their chiptunes cataloged and playable.

  Phase 1 : Finding A Player
  The first step is to find a bit of open source code that can play a particular format. If it’s a library that can handle many formats, like Game Music Emu or Audio Overload SDK, even better (probably). The specific open source license isn’t a big concern for me. I’m almost certain that some of the libraries that SaltyGME currently mixes are somehow incompatible, license-wise. I’ll worry about it when I encounter someone who A) cares, and B) is in a position to do something about it. Historical preservation comes first, and these software libraries aren’t getting any younger (I’m finding some that haven’t been touched in a decade).

  Phase 2 : Test Program
  The next phase is to create a basic test bench program that sends a music file into the library, generates a buffer of audio, and shoves it out to the speakers via PulseAudio’s simple API (people like to rip on PulseAudio, but its simple API really lives up to its name and requires pages less boilerplate code to play a few samples than ALSA).

  Phase 3 : Plug Into Web Player
  After successfully creating the test bench and understanding exactly which source files need to be built, the next phase is to hook it up to the main SaltyGME program via the ad-hoc plugin API I developed. This API requires that a player backend can, at the very least, initialize itself based on a buffer of bytes and generate audio samples into an array of 16-bit numbers. The API also provides functions for managing files with multiple tracks and toggling individual voices/channels if the library supports such a feature. Having the test bench application written beforehand usually smooths out this step.

  But really, I’m just getting started.

  Phase 4 : Collecting A Song Corpus
  Then there is the matter of staging a collection of songs for a given system. It seems like it would just be a matter of finding a large collection of songs for a given format, downloading them in bulk, and mirroring them. Honestly, that’s the easy part. People who are interested in this stuff have been lovingly curating massive collections of these songs for years (see SNESmusic.org for one of the best examples, and they also host a torrent of all their music for really quick and easy hoarding).
  
  In my drive to make this game music website more useful for normal people, the goal is to extract as much metadata as possible to make searching better, and to package the data so that it’s as convenient as possible for users. Whenever I seek to add a new format to the collection, this is the phase where I invariably find that I have to fundamentally modify some of the assumptions I originally made in the player.

  First, there were the NES Sound Format (NSF) files, the original format I wanted to play. These are files that have any number of songs packed into a single file. Playback libraries expose APIs to jump to individual tracks. So the player was designed around that. Game Boy GBS files also fall into this category but present a different challenge vis-à-vis metadata, addressed in the next phase.

  Then, there were the SPC files. Each SPC file is its own song and multiple SPC files are commonly bundled as RAR files. Not wanting to deal with RAR, or any format where I interacted with a general compression API to pull a few files out, I created a custom resource format (inspired by so many I have studied and documented) and compressed it with a simpler compression API. I also had to modify some of the player’s assumptions to deal with this archive format. Genesis VGMs, bundled either in .zip or .7z, followed the same model as SPC in RAR.

  Then it was suggested that I attempt to bring SaltyGME closer to feature parity with Chipamp, rather than just being a Chrome browser frontend for Game Music Emu. When I studied the Portable Sound Format (PSF), I realized it didn’t fit into the player model I already had. PSF uses a sort of shared library model for code execution and I developed another resource archive format to cope with it. So that covers quite a few formats.

  One more architecture challenge arose when I started to study one of the prevailing metadata formats, explained in the next phase.

  Phase 5 : Metadata
  Finally, for the collections to really be useful, I need to harvest that juicy metadata for search and presentation.

  I have created a series of programs and scripts to scrape metadata out of these music files and store it all in a database that drives the website and search engine. I recognize that it’s no good to have a large corpus of songs with minimal metadata and while importing bulk quantities of music, the scripts harshly reject songs that have too little metadata.

  Again, challenges abound. One of the biggest challenges I’m facing is the peculiar quasi-freeform metadata format that emerged as .m3u that takes a form similar to :

  #################################################################
  #
  # GRADIUS2
  # (c) KONAMI  by Furukawa Motoaki, IKACHAN
  #
  #################################################################
  nemesis2.kss::KSS,62,[Nemesis2] (Opening),2:23,,0
  
  nemesis2.kss::KSS,61,[Nemesis2] (Start),7,,0
  
  nemesis2.kss::KSS,43,[Nemesis2] (Air Battle),34,0-
  
  nemesis2.kss::KSS,44,[Nemesis2] (1st. BGM),51,0-
  
  [...]
  

  A lot of file formats (including Game Boy GBS mentioned earlier) store their metadata separately using this format. I have some ideas about tools I can use to help me process this data but I’m pretty sure each one will require some manual intervention.

  As alluded to in phase 4, .m3u presents another architectural challenge : Notice the second field in the CSV .m3u data. That’s a track number. A player can’t expect every track in a bundled chiptune file to be valid, nor to be in any particular order. Thus, I needed to alter the architecture once more to take this into account. However, instead of modifying the SaltyGME player, I simply extended the metadata database to include a playback order which, by default, is the same as the track order but can also accommodate this new issue. This also has the bonus of providing a facility to exclude playback of certain tracks. This comes in handy for many PSF archives which tend to include files that only provide support for other files and aren’t meant to be played on their own.

  Bright Side
  The reward for all of this effort is that the data lands in a proper database in the end. None of it goes back into the chiptune files themselves. This makes further modification easier as all of the data that is indexed and presented on the site comes from the database. Somewhere down the road, I should probably create an API for accessing this metadata.

• duplicate symbol _ff_inverse in MediaLibiOS+FFmpeg-09/libavcodec.a(inverse.o) and MediaLibiOS+FFmpeg-09/libavutil.a(inverse.o)

  29 octobre 2012, par Taha Selim Bebek

  If I create a new project in xcode and add MediaLibiOS to the project it builds without any errors, but if I add it to my existing project there is an error of duplicate symbols in MediaLib iOS. Error goes like this :

  duplicate symbol _ff_inverse in :
  /Users/tbebek/Desktop/4.0_RC/MediaLibiOS+FFmpeg-09/libavcodec.a(inverse.o)
  /Users/tbebek/Desktop/4.0_RC/MediaLibiOS+FFmpeg-09/libavutil.a(inverse.o)
  ld : 1 duplicate symbol for architecture i386
  clang : error : linker command failed with exit code 1 (use -v to see invocation)

  Any ideas ? Thanks.

• I am trying to use the RTSPPlay, project of mooncatventures. But it shows me error like this

  7 octobre 2013, par kamlesh shingarakhiya

  I am trying to use the RTSPPlay, project of mooncatventures. But it shows me error like this.

  Ld /Users/admin/Library/Developer/Xcode/DerivedData/Intercom-bpixnryueeelexfnzxtmgchcfgzq/Build/Products/Debug-iphonesimulator/Intercom.app/Intercom normal i386
  
      cd /Volumes/IPHONE/Intercom
  
      setenv IPHONEOS_DEPLOYMENT_TARGET 6.1
  
      setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
  
      /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.1.sdk -L/Users/admin/Library/Developer/Xcode/DerivedData/Intercom-bpixnryueeelexfnzxtmgchcfgzq/Build/Products/Debug-iphonesimulator -F/Users/admin/Library/Developer/Xcode/DerivedData/Intercom-bpixnryueeelexfnzxtmgchcfgzq/Build/Products/Debug-iphonesimulator -F/Users/admin/Downloads/RTSPPlay-master -filelist /Users/admin/Library/Developer/Xcode/DerivedData/Intercom-bpixnryueeelexfnzxtmgchcfgzq/Build/Intermediates/Intercom.build/Debug-iphonesimulator/Intercom.build/Objects-normal/i386/Intercom.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -Xlinker -no_implicit_dylibs -fobjc-link-runtime -mios-simulator-version-min=6.1 -framework FFmpegDecoder -framework FFPlayer -framework SDL -framework OpenGLES -framework MediaPlayer -framework CoreMedia -framework CoreVideo -framework MobileCoreServices -framework AVFoundation -framework CFNetwork -lbz2 -lxml2 -lz.1.1.3 -lz -framework QuartzCore -framework Security -framework SystemConfiguration -framework UIKit -framework Foundation -framework CoreGraphics -o /Users/admin/Library/Developer/Xcode/DerivedData/Intercom-bpixnryueeelexfnzxtmgchcfgzq/Build/Products/Debug-iphonesimulator/Intercom.app/Intercom
  
  
  
  
  
  
  
  Undefined symbols for architecture i386:
  
    "_SDL_AddTimer", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_CloseAudio", referenced from:
  
        _stream_component_close in FFPlayer(main.o)
  
    "_SDL_CondSignal", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
        _packet_queue_abort in FFPlayer(main.o)
  
        _packet_queue_put in FFPlayer(main.o)
  
    "_SDL_CondWait", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
        _packet_queue_get in FFPlayer(main.o)
  
    "_SDL_CreateCond", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _packet_queue_init in FFPlayer(main.o)
  
    "_SDL_CreateMutex", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _packet_queue_init in FFPlayer(main.o)
  
    "_SDL_CreateRGBSurface", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _video_open in FFPlayer(main.o)
  
    "_SDL_CreateRenderer", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_CreateThread", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _stream_component_open in FFPlayer(main.o)
  
    "_SDL_CreateWindow", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_Delay", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
        _decode_thread in FFPlayer(main.o)
  
    "_SDL_DestroyCond", referenced from:
  
        _do_exit in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
    "_SDL_DestroyMutex", referenced from:
  
        _do_exit in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
    "_SDL_DestroyTexture", referenced from:
  
        _video_display in FFPlayer(main.o)
  
    "_SDL_EventState", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_FillRect", referenced from:
  
        _video_display in FFPlayer(main.o)
  
    "_SDL_FreeSurface", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _do_exit in FFPlayer(main.o)
  
    "_SDL_GL_SetAttribute", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_Init", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_LockSurface", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_SDL_MapRGB", referenced from:
  
        _video_display in FFPlayer(main.o)
  
    "_SDL_OpenAudio", referenced from:
  
        _stream_component_open in FFPlayer(main.o)
  
    "_SDL_PauseAudio", referenced from:
  
        _stream_component_open in FFPlayer(main.o)
  
    "_SDL_PixelFormatEnumToMasks", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _video_open in FFPlayer(main.o)
  
    "_SDL_PollEvent", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_PushEvent", referenced from:
  
        _sdl_refresh_timer_cb in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _decode_thread in FFPlayer(main.o)
  
    "_SDL_RenderPresent", referenced from:
  
        _video_display in FFPlayer(main.o)
  
    "_SDL_SendQuit", referenced from:
  
        -[SDLUIKitDelegate quitSdl] in SDL_uikitappdelegate.o
  
        -[SDLUIKitDelegate applicationWillTerminate:] in SDL_uikitappdelegate.o
  
        -[SDLUIKitDelegate applicationDidEnterBackground:] in SDL_uikitappdelegate.o
  
    "_SDL_UnlockSurface", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_SDL_WaitEvent", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_SDL_WaitThread", referenced from:
  
        _do_exit in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
    "_SDL_mutexP", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
        _packet_queue_get in FFPlayer(main.o)
  
        _packet_queue_abort in FFPlayer(main.o)
  
        _packet_queue_flush in FFPlayer(main.o)
  
        ...
  
    "_SDL_mutexV", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _stream_component_close in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
        _packet_queue_get in FFPlayer(main.o)
  
        _packet_queue_abort in FFPlayer(main.o)
  
        _packet_queue_flush in FFPlayer(main.o)
  
        ...
  
    "_av_audio_convert", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
    "_av_audio_convert_alloc", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
    "_av_audio_convert_free", referenced from:
  
        _stream_component_close in FFPlayer(main.o)
  
        _sdl_audio_callback in FFPlayer(main.o)
  
    "_av_bitstream_filter_next", referenced from:
  
        _show_formats in cmdutils.o
  
    "_av_close_input_file", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_codec_next", referenced from:
  
        _show_formats in cmdutils.o
  
    "_av_dup_packet", referenced from:
  
        _packet_queue_put in FFPlayer(main.o)
  
    "_av_find_input_format", referenced from:
  
        _opt_format in FFPlayer(main.o)
  
    "_av_find_opt", referenced from:
  
        _opt_default in cmdutils.o
  
    "_av_find_stream_info", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_free", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _free_subpicture in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _packet_queue_get in FFPlayer(main.o)
  
    "_av_free_packet", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
        _packet_queue_flush in FFPlayer(main.o)
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_freep", referenced from:
  
        _free_subpicture in FFPlayer(main.o)
  
        _packet_queue_flush in FFPlayer(main.o)
  
    "_av_get_bits_per_sample_format", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
    "_av_get_int", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_av_get_string", referenced from:
  
        _set_context_opts in cmdutils.o
  
    "_av_gettime", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _get_master_clock in FFPlayer(main.o)
  
        _video_display in FFPlayer(main.o)
  
        _get_video_clock in FFPlayer(main.o)
  
        _stream_component_open in FFPlayer(main.o)
  
        _sdl_audio_callback in FFPlayer(main.o)
  
        _stream_pause in FFPlayer(main.o)
  
        ...
  
    "_av_iformat_next", referenced from:
  
        _show_formats in cmdutils.o
  
    "_av_init_packet", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_log", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_malloc", referenced from:
  
        _packet_queue_put in FFPlayer(main.o)
  
    "_av_mallocz", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_av_metadata_get", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_oformat_next", referenced from:
  
        _show_formats in cmdutils.o
  
    "_av_open_input_file", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_protocol_next", referenced from:
  
        _show_formats in cmdutils.o
  
    "_av_read_frame", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_read_pause", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_read_play", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_av_realloc", referenced from:
  
        _opt_default in cmdutils.o
  
    "_av_register_all", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_av_set_string3", referenced from:
  
        _opt_default in cmdutils.o
  
        _set_context_opts in cmdutils.o
  
    "_av_strdup", referenced from:
  
        _parse_options in cmdutils.o
  
    "_av_strlcat", referenced from:
  
        _show_help_options in cmdutils.o
  
    "_av_strlcpy", referenced from:
  
        _show_help_options in cmdutils.o
  
        _SDL_main in FFPlayer(main.o)
  
    "_avcodec_alloc_context2", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_avcodec_alloc_frame", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_avcodec_close", referenced from:
  
        _stream_component_close in FFPlayer(main.o)
  
    "_avcodec_decode_audio3", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
    "_avcodec_decode_subtitle2", referenced from:
  
        _subtitle_thread in FFPlayer(main.o)
  
    "_avcodec_decode_video2", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_avcodec_find_decoder", referenced from:
  
        _stream_component_open in FFPlayer(main.o)
  
    "_avcodec_flush_buffers", referenced from:
  
        _sdl_audio_callback in FFPlayer(main.o)
  
        _video_thread in FFPlayer(main.o)
  
        _subtitle_thread in FFPlayer(main.o)
  
    "_avcodec_open", referenced from:
  
        _stream_component_open in FFPlayer(main.o)
  
    "_avcodec_register_all", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_avcodec_thread_init", referenced from:
  
        _stream_component_open in FFPlayer(main.o)
  
    "_avcodec_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_avdevice_register_all", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_avdevice_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_avfilter_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_avformat_alloc_context", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_avformat_seek_file", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_avformat_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_avpicture_alloc", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_avutil_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_dump_format", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_parse_date", referenced from:
  
        _parse_time_or_die in cmdutils.o
  
    "_sws_getCachedContext", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_sws_getContext", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_sws_scale", referenced from:
  
        _video_thread in FFPlayer(main.o)
  
    "_swscale_version", referenced from:
  
        _print_all_lib_versions in cmdutils.o
  
    "_url_feof", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_url_ferror", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
    "_url_ftell", referenced from:
  
        _SDL_main in FFPlayer(main.o)
  
    "_url_set_interrupt_cb", referenced from:
  
        _decode_thread in FFPlayer(main.o)
  
  ld: symbol(s) not found for architecture i386
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

  Can someone plz help me, thanx guys. I have checked that SDL.Framework and I dont see any problem in it. Does I have to add some library in my project to run this project or in mac.