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• Nix package : Pass build flag —extra-cflags to ffmpeg at compile time

  13 mai 2024, par catleeball

  I'm a little inexperienced with Nix and NixOS and am struggling a bit with this ffmpeg source build. Any advice is appreciated !

  


  Goal

  


  Build ffmpeg from source with --extra-cflags="-pipe -O3 -march=znver3 -ffat-lto-objects", ideally using a flake or overlay or similar so that I can build off the existing ffmpeg nix package and maybe even reproducible builds.

  


  Attempts

  


  I've been trying to follow different advice I've seen online, but looking at ffmpeg in nixpkgs, I'm not sure what I could patch or override. Since configureFlags happens inside the stdenv.mkderivation block, when I try to override it, it doesn't seem to have scope into this variable (and since the derivation explicitly sets onfigurePlatforms = [];, I'm not sure if that would clobber the override changes unless I tried to override the whole long derivation).

  


  Looking at the ffmpeg configure script, it seemed like environment variable cflags / cxxflags won't be respected, but it will take them from the --extra-cflags argument, but I could be missing something.

  


  Flake attempt

  


  Here's an example flake.nix I forked from an example I saw at this github repo

  


  {
  description = "A full build of ffmpeg, including the proprietary stuff";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          config.allowUnfree = true;
        };

        overrides = {
          ffmpeg = pkgs.ffmpeg-full;
          # If this did work, I'm not sure how it would combine with the derivation in the existing package, e.g. if it would get overridden
          configureFlags = [ "--extra-cflags -march=znver3 -O3 -pipe -ffat-lto-objects" ];
          withHeadlessDeps = true;
          nonfreeLicensing = true;
          # more options here once things are working above
        };
      in
      rec {
        packages.ffmpeg-custom = pkgs.ffmpeg-full.override overrides;
        defaultPackage = packages.ffmpeg-custom;
      }
    );
}


  


  when building with nix profile install, I encounter the error :

  


         error: function 'anonymous lambda' called with unexpected argument 'configureFlags'

       at /nix/store/d9wpzgyjlpw1424kw2lyilah6690fnk3-source/pkgs/development/libraries/ffmpeg-full/default.nix:1:1:

            1| { lib, stdenv, buildPackages, ffmpeg, addOpenGLRunpath, pkg-config, perl, texinfo, yasm
             | ^
            2| /*


  


  presumably since configureFlags is defined in the derivation in the original package.

  


  Overlay in configuration.nix attempt

  


  I tried adding this to my /etc/nixos/configuration.nix also without success :

  


  nixpkgs.overlays = [
  (self: super: {
    ffmpeg-full = super.ffmpeg-full.override {
      configureFlags = [
        "--enable-hardcoded-tables"
        "--extra-cflags -march=znver3 -O3 -pipe -ffat-lto-objects"
      ] ++ super.ffmpeg-full.configureFlags;
    };
  })
];


  


  when building with nixos-rebuild switch I get the same error :

  


         error: function 'anonymous lambda' called with unexpected argument 'configureFlags'

       at /nix/store/amxbqlhq11xfrbs4vdsyi04fap0abx0v-nixos-23.11/nixos/pkgs/development/libraries/ffmpeg/generic.nix:3:1:

            2|
            3| { lib, stdenv, buildPackages, removeReferencesTo, addOpenGLRunpath, pkg-config, perl, texinfo, yasm
             | ^
            4|


  


  Context

  


  I have a NixOS machine that does very long-running ffmpeg encodes nearly all the time. I was hoping to rebuild headless ffmpeg with more aggressive cflags and maybe some extra options. I hope to benchmark performance differences between different builds.

  


  I'll probably use this as an excuse to also build ffmpeg with some extra nonfree dependencies too.

  


• avcodec/alsdec : Set channels from data after data is set

  18 mars 2022, par Michael Niedermayer

  avcodec/alsdec : Set channels from data after data is set
  Fixes : out of array write
  
  Fixes : 45624/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-6473487382872064
  
  Fixes : 45626/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-4874997192065024
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Reviewed-by : James Almer <jamrial@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/alsdec.c

• Can I convert a django video upload from a form using ffmpeg before storing the video ?

  5 mai 2014, par GetItDone

  I’ve been stuck for weeks trying to use ffmpeg to convert user uploaded videos to flv. I use heroku to host my website, and store my static and media files on amazon S3 with s3boto. The initial video file will upload fine, however when I retrieve the video and run a celery task (in the same view where the initial video file is uploaded), the new file won’t store on S3. I’ve been trying to get this to work for over a month, with no luck, and really no good resources available for learning how to do this, so I figure maybe if I can get the ffmpeg task to run before storing the video I may be able to get it to work. Unfortunately I’m still not a very advanced at python (or django), so I don’t even know if/how this is possible. Anyone have any ideas ? I am willing to use any solution at this point no matter how ugly, as long as it successfully takes video uploads and converts to flv using ffmpeg, with the resulting file being stored on S3. It doesn’t seem that my situation is very common, because no matter where I look, I cannot find a solution that explains what I should be trying to do. Therefore I will be very appreciative of any guidance. Thanks. My relevant code follows :

  #models.py
  
  def content_file_name(instance, filename):
  
      ext = filename.split('.')[-1]
  
      new_file_name = "remove%s.%s" % (uuid.uuid4(), ext)
  
      return '/'.join(['videos', instance.teacher.username, new_file_name])
  
  
  
  class BroadcastUpload(models.Model):
  
      title = models.CharField(max_length=50, verbose_name=_('Title'))
  
      description = models.TextField(max_length=100, verbose_name=_('Description'))
  
      teacher = models.ForeignKey(User, null=True, blank=True, related_name='teacher')
  
      created_date = models.DateTimeField(auto_now_add=True)
  
      video_upload = models.FileField(upload_to=content_file_name)
  
      flvfilename = models.CharField(max_length=100, null=True, blank=True)
  
      videothumbnail = models.CharField(max_length=100, null=True, blank=True)
  
  
  
  #tasks.py
  
  @task(name='celeryfiles.tasks.convert_flv')
  
  def convert_flv(video_id):
  
      video = BroadcastUpload.objects.get(pk=video_id)
  
      print "ID: %s" % video.id
  
      id = video.id
  
      print "VIDEO NAME: %s" % video.video_upload.name
  
      teacher = video.teacher
  
      print "TEACHER: %s" % teacher
  
      filename = video.video_upload
  
      sourcefile = "%s%s" % (settings.MEDIA_URL, filename)
  
      vidfilename = "%s_%s.flv" % (teacher, video.id)
  
      targetfile = "%svideos/flv/%s" % (settings.MEDIA_URL, vidfilename)
  
      ffmpeg = "ffmpeg -i %s %s" % (sourcefile, vidfilename)
  
      try:
  
          ffmpegresult = subprocess.call(ffmpeg)
  
          #also tried separately with following line:
  
          #ffmpegresult = commands.getoutput(ffmpeg)
  
          print "---------------FFMPEG---------------"
  
          print "FFMPEGRESULT: %s" % ffmpegresult
  
      except Exception as e:
  
          ffmpegresult = None
  
          print("Failed to convert video file %s to %s" % (sourcefile, targetfile))
  
          print(traceback.format_exc())
  
      video.flvfilename = vidfilename
  
      video.save()
  
  
  
  @task(name='celeryfiles.tasks.ffmpeg_image')        
  
  def ffmpeg_image(video_id):
  
      video = BroadcastUpload.objects.get(pk=video_id)
  
      print "ID: %s" %video.id
  
      id = video.id
  
      print "VIDEO NAME: %s" % video.video_upload.name
  
      teacher = video.teacher
  
      print "TEACHER: %s" % teacher
  
      filename = video.video_upload
  
      sourcefile = "%s%s" % (settings.MEDIA_URL, filename)
  
      imagefilename = "%s_%s.png" % (teacher, video.id)
  
      thumbnailfilename = "%svideos/flv/%s" % (settings.MEDIA_URL, thumbnailfilename)
  
      grabimage = "ffmpeg -y -i %s -vframes 1 -ss 00:00:02 -an -vcodec png -f rawvideo -s 320x240 %s" % (sourcefile, thumbnailfilename)
  
      try:        
  
           videothumbnail = subprocess.call(grabimage)
  
           #also tried separately following line:
  
           #videothumbnail = commands.getoutput(grabimage)
  
           print "---------------IMAGE---------------"
  
           print "VIDEOTHUMBNAIL: %s" % videothumbnail
  
      except Exception as e:
  
           videothumbnail = None
  
           print("Failed to convert video file %s to %s" % (sourcefile, thumbnailfilename))
  
           print(traceback.format_exc())
  
      video.videothumbnail = imagefilename
  
      video.save()
  
  
  
  #views.py
  
  def upload_broadcast(request):
  
      if request.method == 'POST':
  
          form = BroadcastUploadForm(request.POST, request.FILES)
  
          if form.is_valid():
  
              upload=form.save()
  
              video_id = upload.id
  
              image_grab = ffmpeg_image.delay(video_id)
  
              video_conversion = convert_flv.delay(video_id)
  
              return HttpResponseRedirect('/current_classes/')
  
      else:
  
          form = BroadcastUploadForm(initial={'teacher': request.user,})
  
      return render_to_response('videos/create_video.html', {'form': form,}, context_instance=RequestContext(request))
  
  
  
  #settings.py
  
  DEFAULT_FILE_STORAGE = 'myapp.s3utils.MediaRootS3BotoStorage'
  
  DEFAULT_S3_PATH = "media"
  
  STATICFILES_STORAGE = 'myapp.s3utils.StaticRootS3BotoStorage'
  
  STATIC_S3_PATH = "static"
  
  AWS_STORAGE_BUCKET_NAME = 'my_bucket'
  
  CLOUDFRONT_DOMAIN = 'domain.cloudfront.net'
  
  AWS_ACCESS_KEY_ID = 'MY_KEY_ID'
  
  AWS_SECRET_ACCESS_KEY = 'MY_SECRET_KEY'
  
  MEDIA_ROOT = '/%s/' % DEFAULT_S3_PATH
  
  MEDIA_URL = 'http://%s/%s/' % (CLOUDFRONT_DOMAIN, DEFAULT_S3_PATH)
  
  ...
  
  
  
  #s3utils.py
  
  from storages.backends.s3boto import S3BotoStorage
  
  from django.utils.functional import SimpleLazyObject
  
  
  
  StaticRootS3BotoStorage = lambda: S3BotoStorage(location='static')
  
  MediaRootS3BotoStorage  = lambda: S3BotoStorage(location='media')

  I can add any other info if needed to help me solve my problem.