Working with HDV
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Working with HDV Avid supports the following High Definition Video (HDV) project types: • 1080i/59.94 HDV • 1080i/50 HDV • 720p/29.97 HDV You can capture from an HDV device, edit in native HDV, and export to an HDV device using these project types. You can also use HDV in other project types, but the system is more efficient and performs better with the dedicated HDV project types. The other project types you can use include: • 1080i/59.94 • 1080i/50 • PAL 25i • NTSC 30i You cannot capture or export native HDV in the non-HDV project types. See the following topics: • Understanding HDV • HDV Basic Workflow • Configuring HDV devices for capture • Capturing and Importing HDV • Mixing Resolutions • Playing Back HDV Media • Rendering and Transcoding HDV Media • Outputting HDV • Long-GOP Splicing for HDV Encoding • Exporting an HDV Transport Stream • Finishing to HD-DVD • Conforming Sequences Created with HDV Media • HDV Compatibility Guidelines • Export to HDV Device Settings Understanding HDV HDV is a low-cost prosumer format that allows you to record HD video onto standard DV videocassettes. This is achieved through the use of interframe compression, where a given frame in the video stream can be composed of information from adjacent frames. Interframe compression is more efficient than frame-based schemes (such as DV 25), allowing high- bandwith HD images to be contained on media designed for standard definition (SD). However, HDV is more difficult to edit since frames are not independent of one another. Avid provides a workflow that allows you to edit natively with HDV-compressed video without requiring a transcode to frame-based media. The Avid application uses a technique called long-GOP splicing when encoding an HDV MPEG-2 sequence for export. For more information, see “Long-GOP Splicing for HDV Encoding”. HDV utilizes MPEG-2 video encoding and MPEG-1 audio encoding. 1080i records at about 25Mbps and 720p records at about 19Mbps. Sony provides HDV cameras that record at 1080i/59.94 and 1080i/50. JVC® cameras record at 720p/29.97 and 720p/23.976. In the 1080i formats, the data rate of the video is reduced before compression by horizontally resizing the video display (raster) from 1920 x 1080 pixels to 1440 x 1080 pixels. In contrast, 720p HDV uses the standard raster size of 1280 x 720. A new resolution, DNxHD-TR (for Thin Raster), improves the performance of 1080i HDV editing. This resolution matches the 1080i HDV raster size, reducing artifacts that would come from repeated compressions when rendering effects and graphics. HDV Basic Workflow A basic workflow for an HDV project is as follows: 1. Select one of the following Avid project types depending on the format in which your HDV camera records: - • 1080i/59.94 HDV - • 1080i/50 HDV - • 720p/29.97 HDV - 2. Do one of the following: - Capture HDV material. - Import an HDV file. The media is brought in as one video track and two 48-kHz audio tracks. 3. Edit the material. - 4. Select the sequence. - 5. Output the sequence back to the HDV device using the Export to HDV Device dialog box. You can export the file in other formats or use Windows Media 9 for export to a third-party HD-DVD authoring system. You can also conform HDV sequences on Symphony™ Nitris® systems. For more information, see “Finishing to HD-DVD” and “Conforming Sequences Created with HDV Media”. Configuring HDV devices for 1394 capture Most Sony HDV devices are capable of recording / outputting in both NTSC and PAL HDV and DV formats. In addition to recording / outputting in native formats, most Sony HDV devices are capable of down converting HDV to DV via the 1394 (IEEE, FireWire, iLINK) port. With several different setting variants and configurations it is essential to properly configure HDV devices prior to starting your Avid editing application. The importance of power cycling Depending on the configuration of the HDV device dictates how the Avid editing application will utilize the HDV device. If the HDV device is configured for an HDV output / record, and it needs to be configured for a DV output / record; the HDV device will not work properly until the Avid editing application is closed and the HDV device is power cycled. In the preceding scenario the operating system recognizes the HDV device is configured for HDV output / record and relays this information to the Avid editing application. If a configuration change is made to the HDV device, such as switching from HDV to DV, neither the operating system nor the Avid editing application are aware of the changes. Closing the Avid editing application and power cycling the HDV device allows the operating system to release the HDV configuration (turning off) and then recognize the DV settings (turning on). The DV settings are then relayed to the Avid editing application and the HDV device works properly. This scenario can be avoided by utilizing the AUTO setting within the IN/OUT REC > VCR HDV/DV settings menu. For more information see the “IN/OUT REC > VCR HDV/DV > AUTO / HDV / DV” and “1080i/59.94 HDV project with HDV tape inserted”. Proper steps for changing HDV device configuration settings: - 1. Close the Avid editing application. - 2. Make applicable HDV device settings / configuration changes. - 3. Power cycle HDV device. - 4. Launch the Avid editing application. Switching between HDV and DV IN/OUT REC > VCR HDV/DV > AUTO / HDV / DV The VCR HDV/DV setting allows for three output modes AUTO, HDV, and DV. The AUTO setting automatically switches between HDV and DV formats (depending on the tape record format) during playback. Though reliable it is recommended to switch the VCR HDV/DV setting to the appropriate tape record format to minimize potential errors during capture. The HDV setting outputs HDV recorded material. The DV setting outputs DV recorded material. IN/OUT REC > i.LINK CONV > ON / OFF The i.LINK CONV setting is used in conjunction with the VCR HDV/DV settings. If not properly set, the i.LINK CONV can cause errors both within the Avid editing application and the HDV device. For more information, see the “1080i/59.94 HDV project with HDV tape inserted” and “30i NTSC project with DV tape inserted” tables. When enabled [ON], the i.LINK CONV setting downconverts HDV to standard definition via the 1394 connection. When disabled [OFF], the 1394 output defaults to the according VCR HDV/DV setting. 1080i/59.94 HDV project with HDV tape inserted VCR HDV/DV i.LINK CONV Result setting setting AUTO* ON Error: No input signal present Should be in a 30i / 25i project for SD downconvert. OFF HDV device is properly configured HDV ON Error: No input signal present Should be in a 30i / 25i project for SD downconvert. OFF HDV device is properly configured DV ON Avid Error: No input signal present HDV Device Error: No output image in “VCR HDV/DV”. Change format. Change the IN/OUT REC settings to AUTO or HDV. OFF Avid Error: No input signal present HDV Device Error: No output image in “VCR HDV/DV”. Change format. Change the IN/OUT REC settings to AUTO or HDV. *Though reliable it is recommended to switch the VCR HDV/DV setting to the appropriate tape record format to minimize potential errors during capture. 30i NTSC project with DV tape inserted VCR HDV/DV i.LINK CONV Result setting setting AUTO* ON HDV device is properly configured OFF HDV device is properly configured HDV ON No Avid Error: No incoming video HDV Device Error: No output image in “VCR HDV/DV”. Change format. Change the IN/OUT REC settings to DV. OFF Avid Error: No input signal present HDV Device Error: No output image in “VCR HDV/DV”. Change format. Change the IN/OUT REC settings to DV. DV ON HDV device is properly configured OFF HDV device is properly configured *Though reliable it is recommended to switch the VCR HDV/DV setting to the appropriate tape record format to minimize potential errors during capture. Capturing and Importing HDV You can capture HDV only through a IEEE 1394 port. You cannot capture HDV through the DV port on a Avid Mojo (non SDI) or Avid Adrenaline hardware. You can import an HDV transport stream file (.m2t). Transport streams combine video and audio for transmission via IEEE 1394. The Avid system separates the transport stream after import or capture into the video and audio for editing. After import or capture, the master clips in the Avid editing system contain HDV long-GOP MPEG-2 video in MXF format and 2 channels of uncompressed 48 kHz 16-bit audio. For more information about long-GOP, see “Long-GOP Splicing for HDV Encoding”. Capturing HDV How you capture HDV material depends on your system configuration: • On a system with Avid Mojo (non SDI) or Avid Adrenaline hardware, you must use a 1394 port on your computer. On a Windows system, the 1394 port must be on an optional IEEE-1394 card installed on a bus separate from the one used by the Avid Mojo or Avid Adrenaline. • On a system with Avid Mojo SDI hardware, use the 1394 port on the Mojo SDI. • On a software-only system, use the 1394 port on the computer. To capture HDV material: 1. Set up an HDV project depending on the format in which your HDV camera records. 2. Select Special > Device menu > IEEE 1394. 3. Select Deck Configuration in the Settings list of the Project window, and configure the HDV device. For more information about configuring decks and cameras, see “Configuring Decks: Basics” in the Help.