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  1. 1. DOC SHOP TRANSCODING PROCESS About This Document The following document will describe how to convert a film into the format used by Hot Docs for Doc Shop viewing. As well, it will explain how to submit the converted film to Hot Docs' server. Overview Hot Docs' Doc Shop is a browser-based application used to find and play online the movies received from filmmakers for this year's festival. Hot Docs displays all film submissions in Flash Video (FLV) format. When a film DVD is received by Hot Docs, it is converted from DVD format to FLV. This conversion process is called transcoding. The transcoding can only take place if the DVD has no copy/file protection. Hot Docs uses an automated process to convert the DVD into the FLV file. Transcoding is inherently lossy, meaning there is some degradation in the video/audio quality. Film makers may want to create the FLV file themselves to ensure that the quality of the FLV film is acceptable. There are numerous software packages on the market which can be used to transcode the video. Before a DVD can be converted into an FLV, it usually must be converted into an intermediate format, such as AVI or MPG. Often, the same software a film maker uses to create a DVD can convert the video into such a format (i.e. AVI, MPG). For Windows users, there is a free application which can be used to convert a DVD into a single MPG file: Vob2Mpg. This is available at http://software.badgerit.com/VOB2MPG.html. Another application, for Mac/Windows/Linux operating systems, is Handbrake, available at http://handbrake.fr/?article=download. FLV transcoding software comes is available in both open-source (free) and licensed versions. These applications can convert files from a video format to Flash Video. They allow you to customize various parameters that affect the quality of the converted video. The minimum parameters recommended by Hot Docs can be found in Section A. The Hot Docs' Doc Shop displays a static image associated with each film. When you submit an FLV file of the DVD submission, you should also supply two accompanying image files. The specifications for these images can be found in Section A. Once the film has been converted into an FLV file, and accompanying images have been created, you can deliver the files to Hot Docs. The simplest and quickest method for sending the files is through ftp. Another method is to burn the files to a CD and mail that CD to Hot Docs.
  2. 2. Summary of Steps for sending Hot Docs a transcoded video 1. Convert the DVD into a single video file, i.e. AVI, MPG 2. Transcode the video file into an FLV file 3. Test the FLV file to make sure it is viewable 4. Create 2 image files of the video 5. Correctly name the files before sending 6. FTP or mail the files to Hot Docs The rest of this document will detail the above steps, with the following constraints: - DVD Conversion to MPG using Vob2Mpg on a Windows-based system - Transcoding the MPG file into an FLV file using ffmpeg on a Windows-based system - Creating 2 screenshots of the video using ffmpeg on a Windows-based system - Using FTP to transfer the 3 files (video FLV file and the 2 image files) to the Hot Docs server
  3. 3. SECTION A: Technical Specifications of Files to Send to Hot Docs As previously noted, other applications and methods exist for transcoding a DVD film into a single FLV file, and for creating image files. Provided that the technical specifications listed below are met, any method can be used to create the 3 files: ------------------ FLV specifications ------------------ Video Parameters ---------------- Video Codec: Sorenson Spark (or On2 VP6, which has higher quality video output) Bit Rate: 1000 kbps Frame Per Second (FPS):25 Video Size: Width = 640 pixels Height = (the value that maintains the original aspect ratio) Audio Parameters ---------------- Audio format: MP3 Stereo Data rate: 48kbps Audio rate: 22050 Hz -------------------------- Image files specifications -------------------------- File Type: JPG Dimensions: 60 x 50 AND 400 x 300 *NOTE* If you have created these 3 files using other means, and do not need to consult the Detailed Steps section of the document, please refer to the section on File Names (Section F), so that the files are correctly named, and then refer to Section G, on sending the files to the Hot Docs server. ******************************************************************** Detailed Steps to create the 3 files to send to Hot Docs (Sections B-G)
  4. 4. SECTION B: Convert the DVD into a single MPG file (Windows) ------------------------------------------------- This section can be skipped if you have already converted the video into a single video file, such as AVI or MPG. The application that will be used to convert the DVD into an MPG file is Vob2Mpg, and can be downloaded here: http://software.badgerit.com/VOB2MPG.html Once you have installed Vob2Mpg, launch the application. It has two fields: one for the input DVD folder, and one for the output folder. Before proceeding, make sure the DVD is inserted in the DVD-ROM drive. For the input field, point it to the DVD's drive and then into the VIDEO_TS folder. That is where the video files (.VOB) are located. Set the output folder to somewhere on the computer, i.e. c:hotdocs. Click 'Start' to begin the process. A 2 hours movie should take approximately 8 - 10 minutes to convert into an MPG file. This process maintains the audio and video quality of the original DVD. When the process is complete, you should have a file in the output folder named something like: VTS_01.mpg SECTION C: Transcode MPG file into FLV (Windows) -------------------------------------- You can skip this section if you have already converted the MPG file into an FLV file. Before transcoding the MPG into FLV, you will need to know the aspect ratio of the video. Two common ratios are 16:9 and 4:3. The aspect ratio is needed to calculate the height value when transcoding. The width value is fixed at 640 pixels. The width value is calculated based on the aspect ratio. For example, the ratio 16:9, with a width of 640, has a calculated height of 360. The aspect ratio 4:3, with the fixed width value of 640, has a calculated height of 480. The application that will be used to convert the MPG file into a Flash video file (FLV) is ffmpeg. The latest version is (unofficially) available here for download: http://tripp.arrozcru.org/. The download is in a compressed format, so you may also need to download and install an unzip program, such as 7zip (http://www.7-zip.org/download.html) to uncompress the ffmpeg installation files. Once you have uncompressed the ffmpeg executable, follow the following steps: 1) open a command-line window, by clicking on Start --> Run, and then enter (without the quotes) quot;cmdquot; and then press <ENTER>. A command line window should open, typically at c:Documents and SettingsUSERNAME. 2) Using the DOS quot;cdquot; command, change to the folder where ffmpeg is installed, i.e. quot;cd c:HotDocsffmpegquot; and then press <ENTER>. To test if you have properly changed to the correct folder, type in quot;ffmpegquot; and press <ENTER>. You should see ffmpeg related text scroll down the screen. If you do not see it, verify the location where ffmpeg was extracted to, and that you have typed the folder location correctly 3) The following command will transcode the MPG file into a Flash file:
  5. 5. ffmpeg -i quot;c:HotDocsVTS_01.mpgquot; -pass 1 -g 240 -qcomp 0.6 -qmax 15 - qdiff 4 -i_qfactor 0.71428572 -b_qfactor 0.76923078 -maxrate 1000k - bufsize 1200k -s 640x480 -b 1000k -refs 5 -subq 6 -r 25 -ab 32k -ar 22050 -ac 1 MyFilm.flv Before entering it, replace the following values: - replace the path of the MPG file with your path, eg: quot;c:HotDocsVTS_01.mpgquot; - replace the width value with the calculated width value eg: 640x480, or 640x360 Once you have entered the command and replaced the necessary values, press <ENTER> to begin the transcoding process. It will take a few minutes, and longer videos take longer to transcode. When the process is completed, you will find the file quot;MyFilm.flvquot; in the folder where ffmpeg was run from. SECTION D: Testing the FLV file (Windows) ------------------------------- Please verify that the FLV file created is viewable and is acceptable to the filmmaker. In order to do this, you will need to open the FLV file with an FLV player. There are many free FLV players available on the web. Among them are Riva FLV Player (http://www.download.com/Riva-FLV-Player/3000-2139_4-127804.html) and FLV Player (http://www.download.com/FLV-Player/3000-13632_4-10467081.html). View the FLV file with the player to make sure it has adequate audio and video. Since the process of transcoding is lossy, there will be a degradation of audio and video. This is especially true if the film has much action (i.e. fast moving subjects). Possible scenarios when viewing the FLV file: - If there is no audio and/or video, redo the transcoding process. - If the quality is less than desirable, view the sample Hot Docs video located at http://hotdocs.ca/SampleVideo. This will provide a basis for comparison, and what to expect in a transcoded flv video. Reading the ffmpeg manual and tweaking some values can change the quality of the video - If after redoing the transcoding process, the file is not viewable or has no audio, send the DVD to Hot Docs for transcoding by Hot Docs.
  6. 6. SECTION E: Extracting screenshots from the video (Windows) ------------------------------------------------ The Doc Shop requires two image files (JPG format) for each film, each displaying the same image, but having different size dimensions. It is recommended that the image be a frame from the film. When Hot Docs receives a DVD, we select a random frame and create 2 image files. Having the filmmaker select the frame ensures that an appropriate image represents the film. Any method can be used to create the two image files, but they must adhere to the size dimensions mentioned in the Overview [60 x 50 AND 400 x 300]. The following steps show how to use ffmpeg to extract the image files: NOTE: The images are identical in content, but are different sizes 1) open a command-line window, by clicking on Start --> Run, and then enter (without the quotes) quot;cmdquot; and then press <ENTER> 2) A command line window should open, typically at c:Documents and SettingsUSERNAME. Using the DOS quot;cdquot; command, change to the folder where ffmpeg is installed, i.e. quot;cd c:HotDocsffmpegquot; and then press <ENTER>. To test if you have properly changed to the correct folder, type in quot;ffmpegquot; and press <ENTER>. You should see ffmpeg related text scroll down the screen. If you do not see it, verify the location for ffmpeg, and that you have typed the folder location correctly - Enter the following command to create a 60x50 jpg file, replacing H,MM, and SS with the hour, minutes, and seconds of the frame you want captured (the command can take up to a few minutes to run as it extracts the image): - ffmpeg -i quot;c:HotDocsVTS_01.mpgquot; -ss H:MM:SS.00 -sameq -vframes 1 -s 60x50 x%01d_small.jpg - For example, the following command captures the frame at 41 minutes and 10 seconds: ffmpeg -i quot;c:HotDocsVTS_01.mpgquot; -ss 0:41:10.00 -sameq -vframes 1 -s 60x50 x%01d_small.jpg 3) Enter the following command to create a 400x300 jpg file, replacing H,MM, and SS with the hour, minutes, and seconds of the frame you want captured (use the same time values as used in step 2 above: - ffmpeg -i quot;c:HotDocsVTS_01.mpgquot; -ss H:MM:SS.00 -sameq -vframes 1 -s 400x300 x%01d_big.jpg
  7. 7. SECTION F: File Naming ---------------------- When Hot Docs receives the files (the 2 image files and the FLV file), we need to know which film these files belong to. Upon submitting the film entry on the web (by filling out the online Hot Docs form), you should have received a Film ID. This is a 5-digit number used to denote the film. If you do not have one, please contact Hot Docs at submissions@hotdocs.ca to retrieve the Film ID. The 3 files can only be mailed or uploaded with that 5-digit value. The files should be named in the following manner: - FLV : FILMID_2.flv (example: 12345_2.flv) - JPG image A (60x50) : FILMID_a.jpg (example: 12345_a.jpg) - JPG image B (400x300) : FILMID_b.jpg (example: 12345_b.jpg) SECTION G: Sending the files to Hot Docs ---------------------------------------- There are to two methods to send the files to Hot Docs: 1) Mail 2) FTP (uploading to Hot Docs' server) Sending by mail: - Burn the 3 files to a CD/DVD - Label the disc with the FilmID - Mail it to the Hot Docs address FTP the file: You will need an FTP client to perform this step. Most web browsers have built-in ftp clients, and there are free ones available, such as FileZilla ( http://filezilla- project.org/download.php). You will need to login to connect to the Hot Docs server to upload (send) the files. Once you login, by entering the username and password below, you will need to change to the quot;incomingquot; folder, and then copy the 3 files to the incoming folder. Since the FLV file will be large, the upload could take quite a while (in some cases, over an hour). To verify the files were sent correctly, check that the file sizes of the files uploaded match the files on your machine. If they do not match, you will need to upload the files again. Due to security concerns, in order to resend a file, you will have to contact submissions@hotdocs.ca and notify them that a film file is incomplete, and needs to be resent. FTP Information: ftp://docshop.hotdocs.ca User: ftpuser Password: !F173hd?

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