ASF Direct Writer filter for iuVCS, iuVCR and WMV Direct




The Microsoft® ASF container allows to store video and audio streams encoded by third-party codecs, not built-in Windows Media Audio/Video codecs only. ASF Direct Writer filter is intended for capture in ASF file format using most of codecs installed on you system. It is guarantied excellent audio-video streams synchronization. This synchronization is preserved if you re-encode the file into other formats, MPEG1/2 for example. That is using ASF Direct Writer is the best way to create your own Video CD and DVD disks from analog sources, such VHS and so on.

For DVD creation purposes you should use codecs that preserve interlace structure of the video frames (Morgan MJPEG, Pic Video MJPEG, Mainconcept DV codecs for example).

ASF Direct Writer is attached to the iuVCS or iuVCR capture utilities. Other capture programs are not supported.

The filter has been tested under OS Windows XP and Vista. Successfully tested codecs are listed below.


·        Morgan MJPEG V3

·        Pic Video M-JPEG 3

·        Pic Video Lossless MJPEG

·        Pic Video Wavelet 2000

·        Huffyuv 2.1.1

·        Mainconcept DV 2.0.4

·        DivX 5.0.3

·        XviD MPEG-4



·        Microsoft MPEG1 Layer 3 (distributed with Windows XP)

·        Windows Media Audio V2


Note: for Pic Video Lossless MJPEG and Wavelet 2000 codecs you should use their “Video For Windows” implementations (that marked by red color in the codec selection combo box in iuVCR).

Also supports internal codecs such as Windows Media Video/Audio and so on.


System requirements

·        OS Microsoft™ Windows® 2000, XP, 2003, Vista (OS Windows XP recommended);

·        DirectX 8.1 or higher (DirectX 9.0c recommended);

·        Windows Media Encoder 9;

·        Video capture utility iuVCS (version 0.9.03 or higher) or iuVCR (version 4.9.2 or higher).


Installation and usage

The ASF Direct Writer setup program attaches this filter to the iuVCR automatically. You can select ASF Direct Writer filter in the iuVCR in the “Muxer” group of the “Video” tab (see Fig. 1).

Fig. 1. Activating ASF Direct Writer filter in the iuVCR.


On the Fig. 2 is shown ASF Direct Writer property page. To access it, click “Configure” button on the “Muxer” group in iuVCR.

Fig. 2. ASF Direct Writer filter options.


The most significant parameter is the “Use unbuffered I/O”. It is recommended always turned this parameter on. For some codecs (Pic Video Lossless MJPEG for example) this is critical.

The “To suspend capture when the signal vanishes” option allows you to temporarily suspend video/audio capture when the video signal disappears. Between every two scenes (at the juncture) the marker will be added. These markers are displayed in the WMV Direct and other software (i.e. Windows Media Player). Its can be used to fast detect scenes junctures.

If you want to use “To add markers when the channel logo appears or disappears (the iuLab Logo Detector is required)” option you should add the “iuLab Logo Detector” filter in the iuVCR/iuVCS.

Information about captured video and sound is shown on the “Statistics” group. Captured and dropped samples and bytes are counted for both audio and video streams. Only come to the writer filter samples are counted. If samples were dropped by capture application then they should not be indicated on the “Samples Dropped” field.

You should select and configure appropriate video codec in the iuVCR just as for AVI container. Sound codec and its parameters should be specified on the “Audio” tab in iuVCR. It is allowed to capture video only, without sound.

Don’t recommended use PCM audio format when DivX, XviD and so on video codec used. With this codecs it is desirable use MPEG1 Layer 3 or Windows Media Audio codec.

Playing captured file is possible in the various software players (Windows Media Player for example). Re-encoding into another format is possible in the video editors and encoders that supports ASF container.

Starting with version the ASF Direct Writer filter can determine the used codecs names. This information is saved in the ASF file header and displayed in the software players (for example in the Windows Media Player). In some cases the determination can be erroneous (for example, if more than one VfW-version of the MJPEG codecs is installed on your system).

To edit captured file you may use any video editors that supports ASF files. To edit without recompress video you should use WMV Direct utility. It is the best way to create your own DVD disks from analog sources.

In some cases two pass encoding in the Canopus Procoder may be not work. The reason of it is not exactly correct support for ASF files in this encoder. In this case is recommended to use another encoder (TMPGEnc for example).

If your computer has Internet connection you can check update for ASF Direct Writer. Press “Check update…” button to check available updates on the Web.


Using internal codecs

ASF Direct Writer filter allows using internal codecs such as Windows Media Video/Audio and so on (Fig. 3). Also the internal deinterlace filter is supported.


Fig. 3. Using internal codecs.



Output to the network

ASF Direct Writer filter allows to write video and audio to the network. To enable broadcasting video to the network turn on “Allow output to the network” option in the “Network” group. The “Port” and “Max clients” parameters specify HTTP port number and maximum clients count, correspondingly. If port number is set to 0 then it will be determined automatically on client connecting.

To view video on another computer on the network run Windows Media Player on it and select File®Open URL-address menu command. Specify string like it: “http://servername:port”. Here servername is the computer name on which the iuVCR is running and port is the port number specified in the ASF Direct Writer property page. If you specified port 0 on the ASF Direct Writer then you should use string like this: “http://servername”.

On the local computer you may use string “http://localhost:port”.

If you want to write to the network only, you must turn on “Disable output to the file” option.

It is recommended to use PCM sound format when output to the network used.

On the “Statistics” group the clients count are shown. Click to the button on the right of the “Clients count” field to view IP-addresses of connected clients.

Note that there is some time latency can appeared while data writing to the network. This latency may reach up to 25 sec.


Using ASF Direct Writer with the WMV Direct

The WMV Direct and higher allows to view and capture the network video broadcasting.

You can capture live translation without registering ASF Direct Writer if the internal codecs (“Windows Media Video”, “Windows Media Audio”, “Microsoft MPEG-4”) are used in this translation.