Recherche avancée

Sur d’autres sites (5183)

• yet another screenshot encoding exercise with ffmpeg - stuck at getting AVFrame from ALT::CImage - VC++

  11 septembre 2013, par sith

  Total AV newbee here - trying to learn the ropes on using FFMpeg functions to encode movies. On searching for tutorials I found a few similar questions that I have linked here for reference :

  Encoding a screenshot into a video using FFMPEG

  [Libav-user] Encoding a screenshot into a video using FFMPEG

  Save bitmap to video (libavcodec ffmpeg)

  When converting from RGB to YUV using ffmpeg the video file the color is spread why ?

  How to convert RGB from YUV420p for ffmpeg encoder ?

  Encode bmp sequence with libavcodec...Help !

  Not able to encode image with ffmpeg

  For my setup FFMPEG is on VS12 - VC++ with MFC on win7.

  With the help of above samples, I am able to get "some" output from the encoder, but I am not sure in what format or state the output has been encoded. Neither VLC nor WMP can play this file. It does not even seem to recognize the metadata in the file to display the FPS or video length. What would normally cause that ? Also any pointers on what could be going wrong and how to approach fixing the problems would be great. [1]

  Here is the flow of my code :

  Step1 : capture desktop on to a CImg :

  int W=GetSystemMetrics(SM_CXSCREEN), H=GetSystemMetrics(SM_CYSCREEN), bpp=24; 
  
  CImage cImg; cImg.Create(W,H,bpp) 
  
  HDC hDC = cImg.GetDC(); 
  
  CWindowDC winDC(GetDesktopWindow()); 
  
  
  
  BitBlt(hDC, 0,0, rez.W(), rez.H(), winDC.m_hDC, 0, 0, SRCCOPY);

  At this point I am able to dump a screen shot into a bmp file -
  using cImg.Save( _T("test.bmp"), Gdiplus::ImageFormatBMP) ;

  Step2 : Extract the BMP bits from the CImg.

  HBITMAP hBitmap = (HBITMAP)cImg;
  
  HDC memDC = CreateCompatibleDC(NULL);
  
  SelectObject( memDC, hBitmap );
  
  
  
  BITMAPINFO bmi; // initialized bmi with {W,-H, plane=1, bitCount=24, comp=BI_RGB, size=W*H*3 }
  
  << removed bmi init code for conciseness. >>>
  
  
  
  BYTE *rgb24Data = new BYTE[W*H*3]; // 3 for 24bpp. 4 for 32...
  
  int ret = GetDIBits(memDC, hBitmap, 0, H, rgb24Data, &bmi, DIB_RGB_COLORS);

  At this point I faithfully believe rgb24Data points to pixel data :) - copied out of the cImg bitmap

  Step 3 : next I try to create an AV frame with the rgb24Data got from this CImg. Also this is where I have a massive knowledge gap. I am going to try and recover

  // setup the codecs and contexts here as per mohM's post
  
  
  
  AVCodec *currCodec = avcodec_find_encoder(CODEC_ID_MPEG4);
  
  
  
  AVCodecContext *codeCtxt = avcodec_alloc_context();  // init this with bate=400k, W, H,
  
  << removed codeCtxt init code for conciseness. >>>   //  time base 1/25, gop=10, max_b=1, fmt=YUV420
  
  
  
  avcodec_open(codeCtxt, currCodec);
  
  
  
  SwsContext *currSWSCtxt = sws_getContext( W, H, AV_PIX_FMT_RGB24, // FROM
  
                                            W, H, AV_PIX_FMT_YUV420P, // TO
  
                                            SWS_FAST_BILINEAR,
  
                                            NULL, NULL, NULL);
  
  
  
  // allocate and fill AVFrame
  
  int numBytes = avpicture_get_size(PIX_FMT_YUV420P, W, H);
  
  uint8_t *buffer=new uint8_t[numBytes];
  
  AVFrame *avFrame = avcodec_alloc_frame();
  
  avpicture_fill( (AVPicture*)avFrame, buffer, PIX_FMT_YUV420P, W, H );

  Step 4 : transform the data frame into YUV420P as we fill the frame.

  uint8_t * inData[1] = { rgb24Data };
  
  int inLinesize[1] = { 3*W }; // RGB stride
  
  sws_scale( currSWSCtxt, inData, inLinesize, 0, H,
  
             avFrame->data, avFrame->linesize);

  step 5 encode the frame and write out the output buffer into a file.

  int out_size = avcodec_encode_video( codeCtxt,
  
                                       outBuf,
  
                                       outBufSize,
  
                                       avFrame );
  
  
  
  fwrite(outBuf, 1, outBufSize, outFile );

  finally I close the file off with [0x00 0x00 0x01 0xb7]

  The first hint of things gone haywire is that for a 50 screens of 1920X1080 at 24bpp encoded at 25fps gives me a 507MB unplayable-mpeg file.

  As mentioned earlier, neither VLC nor WMP can play this file nor they even recognize the metadata in the file to display the FPS or video length. What would normally cause that ? Also any pointers on what could be going wrong and how to approach fixing the problems would be great. [2]

  Any guidance is much appreciated.

• I tried to play the audio on Alexa skill from my S3 Bucket, from the test tab, **it show but in fact, I can't hear any sound

  19 avril 2022, par Siti Mayna

  So I tried to play the audio on Alexa skill from my S3 Bucket, from the test tab, it show but in fact, I can't hear any sound. Another fact is, that I tried to use the sample audio from https://developer.amazon.com/en-US/docs/alexa/custom-skills/ask-soundlibrary.html and it is worked, but why it won't work when it comes from my own S3 Bucket ?

  


  Notes :

  


  I've tried to test the skill using my mobile phone also.

  


  I've tried to encode the audio using FFmpeg.

  


  I've tried to use Jovo to convert the audio. https://v3.jovo.tech/audio-converter

  


  I don't know how to fix this error.

  


  There is no error message on cloud watch.

  


  Assumptions :
There is some problem related to the audio resources or there is more set to play audio from S3 Bucket since the sample audio is working.

  


  Steps to reproduce :

  


  


  Build the interaction model

  


  


  


  Encode the audio to make it Alexa skill friendly (fulfill the requirements, like sample rate, etc), I used and tried all of these :

  


  


  A :

  


  ffmpeg -i  -ac 2 -codec:a libmp3lame -b:a 48k -ar 16000 -write_xing 0 


  


  B :

  


  ffmpeg -i  -ac 2 -codec:a libmp3lame -b:a 48k -ar 24000 -write_xing 0 


  


  C :

  


  ffmpeg -y -i input.mp3 -ar 16000 -ab 48k -codec:a libmp3lame -ac 1 output.mp3


  


  


  Upload the audio resources on S3Bucket
Audio sample on s3 storage but none of them are produce any sounds

  


  


  


  Use the link and insert it to APLA.json

  


  


  
    {
      "type": "APLA",
      "version": "0.91",
      "description": "Simple document that generates speech",
      "mainTemplate": {
        "parameters": [
          "payload"
        ],
        "type": "Sequencer",
        "items": [
          {
            "type": "Audio",
            "source": "https://72578561-d9d8-47b4-811c-cafbcbc5ddb9-us-east-1.s3.amazonaws.com/Media/one-small-step-alexa-24.mp3"
          }
        ]
      }
    }



  


  notes : I change the link sources based on audio that I tried.

  


  


  the intent on lambda_function.py :

  


  


  def _load_apl_document(file_path):
    # type: (str) -> Dict[str, Any]
    """Load the apl json document at the path into a dict object."""
    with open(file_path) as f:
        return json.load(f)

class LaunchRequestHandler(AbstractRequestHandler):
    """Handler for Skill Launch."""
    def can_handle(self, handler_input):
        # type: (HandlerInput) -> bool

        return ask_utils.is_request_type("LaunchRequest")(handler_input)

    def handle(self, handler_input):
        # type: (HandlerInput) -> Response
        logger.info("In LaunchRequestHandler")

        # type: (HandlerInput) -> Response
        speak_output = "Hello World!"
        # .ask("add a reprompt if you want to keep the session open for the user to respond")

        return (
            handler_input.response_builder
                #.speak(speak_output)
                .add_directive(
                        RenderDocumentDirective(
                            token="pagerToken",
                            document=_load_apl_document("APLA.json"),
                            datasources={}
                        )
                    )
                .response
        )


  


  


  Deploy

  


  


  


  Test it

  


  


  


  The result of the test on my end :

The response for testing

  


  


  the JSON response :

  


  {
    "body": {
        "version": "1.0",
        "response": {
            "directives": [
                {
                    "type": "Alexa.Presentation.APLA.RenderDocument",
                    "token": "pagerToken",
                    "document": {
                        "type": "APLA",
                        "version": "0.91",
                        "description": "Simple document that generates speech",
                        "mainTemplate": {
                            "parameters": [
                                "payload"
                            ],
                            "type": "Sequencer",
                            "items": [
                                {
                                    "type": "Audio",
                                    "source": "https://72578561-d9d8-47b4-811c-cafbcbc5ddb9-us-east-1.s3.amazonaws.com/Media/one-small-step-alexa-24.mp3"
                                }
                            ]
                        }
                    },
                    "datasources": {}
                }
            ],
            "type": "_DEFAULT_RESPONSE"
        },
        "sessionAttributes": {},
        "userAgent": "ask-python/1.16.1 Python/3.7.12"
    }
}


  


  


  On my cloud Watch :
Cloud Watch

  


  


• "File doesn't exist" - streamio FFMPEG on screenshot after create method

  3 mai 2013, par dodgerogers747

  I have videos being directly uploaded to S3 using Amazon's CORS configuration. Videos are uploaded via a dedicated S3 form, once they have been uploaded successfully the URL of the video is appended to the @video.file hidden_field via javascript and then the video saves.

  I can't get this after_save method to work which takes a screenshot of the video and saves it to S3 via carrierwave after the video has been saved as a rails object. ( It was previously working using a carrierwave video upload instance )

  It errors out withErrno::ENOENT - No such file or directory - the file 'http://bucket-name.s3.amazonaws.com/uploads/video/file/secure-random-hex/video_name.m4v' does not exist: I have tried running this method as a class method to call it from the console but it always comes back with the same error, even though the video exists.

  My bucket is set to public, read and write. How come it doesn't think the file exists ?

  If anyone needs more code just shout, thanks in advance.

  application trace

  Started POST "/videos" for 127.0.0.1 at 2013-05-03 10:48:07 -0700
  
  Processing by VideosController#create as JS
  
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"MAHxrVcmPDtVIMfDWZBwL0YnzaAaAe1PTGip5M4OVoY=", "video"=>{"user_id"=>"5", "file"=>"http://bucket-name.s3.amazonaws.com/uploads/video/file/secure-random-hex/video.m4v"}}
  
    User Load (0.3ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 5 LIMIT 1
  
     (0.1ms)  BEGIN
  
    SQL (20.5ms)  INSERT INTO `videos` (`created_at`, `file`, `question_id`, `screenshot`, `updated_at`, `user_id`) VALUES ('2013-05-03 17:48:07', 'http://teebox-network.s3.amazonaws.com/uploads/video/file/secure-random-hex/video.m4v', NULL, NULL, '2013-05-03 17:48:07', 5)
  
     (44.0ms)  ROLLBACK
  
  Completed 500 Internal Server Error in 71ms
  
  
  
  Errno::ENOENT - No such file or directory - the file 'http://teebox-network.s3.amazonaws.com/uploads/video/file/secure-random-hex/video.m4v' does not exist:
  
    (gem) streamio-ffmpeg-0.9.0/lib/ffmpeg/movie.rb:10:in `initialize'
  
    app/models/video.rb:25:in `new'
  
    app/models/video.rb:25:in `take_screenshot'

  video.rb

    attr_accessible :user_id, :question_id, :file, :screenshot
  
    belongs_to :question
  
    belongs_to :user
  
  
  
    default_scope order('created_at DESC')
  
  
  
    after_create :take_screenshot
  
  
  
    mount_uploader :screenshot, ImageUploader
  
  
  
    validates_presence_of :user_id, :file
  
  
  
    def take_screenshot
  
      FFMPEG.ffmpeg_binary = '/opt/local/bin/ffmpeg'
  
      movie = FFMPEG::Movie.new("#{self.file}")
  
      self.screenshot = movie.screenshot("#{Rails.root}/public/uploads/tmp/screenshots/#{File.basename(self.file)}.jpg", seek_time: 2 )
  
      self.save!
  
    end

  videos/_form.html.erb

  <form action="http://bucket-name.s3.amazonaws.com" data-remote="true" class="direct-upload" enctype="multipart/form-data" method="post">
  
    <input type="hidden" />
  
    <input type="hidden" value="ACCESS_KEY" />
  
    <input type="hidden" value="public-read" />
  
    <input type="hidden" />
  
    <input type="hidden" />
  
    <input type="hidden" value="201" />
  
    <input type="file" />
  
  </form>
  
  
  
  &lt;%= form_for @video, html: { multipart: true, id: "new_video" }, remote: true do |f| %>
  
          &lt;% if @video.errors.any? %>
  
      <div>
  
      <h2>&lt;%= pluralize(@video.errors.count, "error") %> prohibited this post from being saved:</h2>
  
  
  
    <ul>
  
      &lt;% @video.errors.full_messages.each do |msg| %>
  
          <li>&lt;%= msg %></li>
  
          &lt;% end %>
  
      </ul>
  
      </div>
  
  &lt;% end %>
  
  
  
      &lt;%= f.hidden_field :user_id, value: current_user.id %>
  
      &lt;%= f.hidden_field :file %><br />
  
  
  
      &lt;% end %>

  ImageUploader

  class ImageUploader < CarrierWave::Uploader::Base
  
  
  
    include CarrierWave::RMagick
  
  
  
     include Sprockets::Helpers::RailsHelper
  
     include Sprockets::Helpers::IsolatedHelper
  
  
  
    storage :fog
  
  
  
    before :store, :remember_cache_id
  
    after :store, :delete_tmp_dir
  
  
  
      def cache_dir
  
        Rails.root.join('public/uploads/tmp/') 
  
      end
  
  
  
      def remember_cache_id(new_file)
  
        @cache_id_was = cache_id
  
      end
  
  
  
      def delete_tmp_dir(new_file)
  
        if @cache_id_was.present? && @cache_id_was =~ /\A[\d]{8}\-[\d]{4}\-[\d]+\-[\d]{4}\z/
  
          FileUtils.rm_rf(File.join(root, cache_dir, @cache_id_was))
  
        end
  
      end
  
  
  
    process resize_and_pad: [306, 150, '#000']
  
  
  
    def store_dir
  
      "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  
    end
  
  
  
    def extension_white_list
  
      %w(jpg)
  
      # %w(ogg ogv 3gp mp4 m4v webm mov)
  
    end