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• Seeking Guidance on Audio Development Libraries for Playing Various Music Formats on iOS [closed]

  3 décembre 2023, par FaiChou

  I am exploring audio development and am overwhelmed by the numerous libraries available :

  


  

  • AVFoundation

  


  • MediaPlayer

  


  • AVFAudio

  


  • Audio Engine

  


  • CoreAudio

  


  • AudioToolbox

  


  • Audio Unit

  


  


  Which of these should I use to play both network or local music files (flac/wav/mp3/aac/wma/ogg) ? What are their specific roles ?

  


  My understanding is that I should use ffmpeg for demuxing to unpackage, then decode the stream to get PCM samples, possibly using Audio Engine for playback. Is this a software decoding method ? For Apple-supported formats like mp3, can I bypass ffmpeg for decoding ? Which library would be most suitable in this case ?

  


  Additionally, how do I extract metadata (song name, artist, cover, lyrics, etc.) from music files ? Apple's own solutions seem to support only ID3 or iTunes tags. How should I handle other formats like wav/flac ?

  


  The two links below are the resources I've referenced, but they seem outdated. My search for newer, reliable explanations has been fruitless.

  


  

  • whats-the-difference-between-the-apple-audio-frameworks

  


  • Core Audio Essentials

  


  


• CVAT error during installation of development version

  28 novembre 2022, par Raman

  I'm trying to install development version of CVAT according to official instruction but struggling at the step of requirements.txt applying :

  


  pip install -r cvat/requirements/development.txt


  


  ... with following error :

  


  Skipping wheel build for av, due to binaries being disabled for it.
Skipping wheel build for datumaro, due to binaries being disabled for it.
Installing collected packages: wrapt, tf-estimator-nightly, termcolor, tensorboard-plugin-wit, Shapely, rules, rope, rjsmin, rcssmin, pytz, pyasn1, patool, mistune, mccabe, libclang, keras, itypes, flatbuffers, entrypoint2, EasyProcess, dj-pagination, diskcache, av, addict, Werkzeug, urllib3, uritemplate, typing-extensions, tqdm, tornado, toml, threadpoolctl, tensorflow-io-gcs-filesystem, tensorboard-data-server, sqlparse, smmap, six, ruamel.yaml.clib, rsa, redis, PyYAML, pyunpack, pyrsistent, pyparsing, pylogbeat, pyjwt, Pygments, pycparser, pyasn1-modules, protobuf, Pillow, oauthlib, numpy, networkx, natsort, MarkupSafe, Markdown, lxml, lazy-object-proxy, kiwisolver, joblib, jmespath, isort, inflection, idna, google-crc32c, gast, fonttools, dnspython, django-extensions, deprecated, defusedxml, cycler, click, charset-normalizer, certifi, cachetools, attrs, asgiref, absl-py, tensorboardX, snakeviz, scipy, ruamel.yaml, rq, requests, python3-openid, python-ldap, python-dateutil, pdf2image, packaging, orderedmultidict, opt-einsum, opencv-python-headless, opencv-python, keras-preprocessing, jsonschema, jinja2, isodate, h5py, grpcio, googleapis-common-protos, google-resumable-media, google-pasta, google-auth, gitdb, Django, cffi, astunparse, astroid, scikit-learn, requests-oauthlib, pylint, pandas, matplotlib, limits, google-api-core, GitPython, furl, djangorestframework, django-sendfile2, django-rq, django-filter, django-cors-headers, django-auth-ldap, django-appconf, cryptography, croniter, coreschema, botocore, azure-core, s3transfer, rq-scheduler, python-logstash-async, pylint-plugin-utils, pycocotools, open3d, msrest, google-cloud-core, google-auth-oauthlib, drf-spectacular, django-rest-auth, django-compressor, coreapi, tensorboard, pylint-django, google-cloud-storage, django-allauth, datumaro, boto3, azure-storage-blob, tensorflow
  Running setup.py install for av ... error
  error: subprocess-exited-with-error
  
  × Running setup.py install for av did not run successfully.
  │ exit code: 1
  ╰─> [50 lines of output]
      running install
      /Users/dd/cvat/.env/lib/python3.9/site-packages/setuptools/command/install.py:34: SetuptoolsDeprecationWarning: setup.py install is deprecated. Use build and pip and other standards-based tools.
        warnings.warn(
      running build
      running build_py
      creating build
      creating build/lib.macosx-12.4-x86_64-cpython-39
      creating build/lib.macosx-12.4-x86_64-cpython-39/av
      copying av/deprecation.py -> build/lib.macosx-12.4-x86_64-cpython-39/av
      copying av/datasets.py -> build/lib.macosx-12.4-x86_64-cpython-39/av
      copying av/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av
      copying av/__main__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/video
      copying av/video/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/video
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/codec
      copying av/codec/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/codec
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/container
      copying av/container/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/container
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/audio
      copying av/audio/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/audio
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/subtitles
      copying av/subtitles/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/subtitles
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/filter
      copying av/filter/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/filter
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/sidedata
      copying av/sidedata/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/sidedata
      creating build/lib.macosx-12.4-x86_64-cpython-39/av/data
      copying av/data/__init__.py -> build/lib.macosx-12.4-x86_64-cpython-39/av/data
      running build_ext
      running config
      PyAV: 8.0.2 (unknown commit)
      Python: 3.9.10 (main, Jun 28 2022, 17:49:16) \n[Clang 13.1.6 (clang-1316.0.21.2.5)]
      platform: macOS-12.4-x86_64-i386-64bit
      extension_extra:
          include_dirs: [b'include']
          libraries: []
          library_dirs: []
          define_macros: []
          runtime_library_dirs: []
      config_macros:
          PYAV_COMMIT_STR="unknown-commit"
          PYAV_VERSION=8.0.2
          PYAV_VERSION_STR="8.0.2"
      Could not find libavformat with pkg-config.
      Could not find libavcodec with pkg-config.
      Could not find libavdevice with pkg-config.
      Could not find libavutil with pkg-config.
      Could not find libavfilter with pkg-config.
      Could not find libswscale with pkg-config.
      Could not find libswresample with pkg-config.
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> av


  


  I have already tried suggested fixes, but no luck :
https://github.com/openvinotoolkit/cvat/issues/4406

  


  Environment :

  


  

  • MacBook Pro (Intel x64)

  


  • macOS Monterey (Version 12.4)

  


  • (pyenv) Python 3.9.10

  


  


  What other options could be applied to fix it ?

  


• ffmpeg development recompile only changed part on windows

  8 décembre 2020, par Harry

  New to ffmpeg development, i am trying to develop a patch for a specific demuxer in avformat and sure i want to be able to test my changes without recompiling all parts of ffmpeg again as it takes about an hour. My toolchain is set up as per https://ffmpeg.org/platform.html 4.1.1. Using mingw64.exe, it was no problem to compile an initial version :

  


  ./configure --disable-static --enable-shared --enable-gpl
make -j4


  


  Voila, i have a shared build, means the .exe and .dll files are built and i can run the program successfully.

  


  Now when i change some code , e.g. in libavformat/pcm.c, i can recompile this part easily by doing

  


  make pcm.o


  


  make will even recognize automatically if there were changes to the code and only rebuild the single .o file. But when executing make in the root path of the ffmpeg source again, it will always recompile all .o files which of course something i want to avoid.

  


  I tried disabling some components e.g. by doing

  


  ./configure --disable-static --enable-shared --enable-avisynth --enable-gpl --disable-avcodec --disable-avdevice --disable-avfilter


  


  But this way, i am only getting a new avutil.dll, avscale.dll and avresample.dll but no avformat.dll (which i dont understand because i dont disable avformat), also it seems to recompile the parts instead of re-using and just link the existing .o files together.

  


  How could i tell the make command not to compile anything but instead just link all the existing .o files - and only for avformat instead of all parts ?