19 Capturing media (intro)
19.1 Capturing using Cinelerra
19.2 Capturing using dvgrab
19.1 Capturing using Cinelerra
19.1.1 Cinelerra recording functions19.1.2 Batch recording
19.1.3 Editing tuner information
19.1.1 Cinelerra recording functions
Ideally, all media would be stored on hard drives, CD-ROM, flash, or DVD and loading it into Cinelerra would be a matter of loading a file. In reality, very few sources of media can be accessed like a filesystem but instead rely on tape transport mechanisms and dumb I/O mechanisms to transfer the data to computers. These media types are imported into Cinelerra through the Record dialog.
The first step in recording is to configure the input device. In Settings->preferences are a number of recording parameters described in configuration See section Recording. These parameters apply to recording no matter what the project settings are, because the recording parameters are usually the maximum capability of the recording hardware while project settings come and go.
Go to File->record to record a dumb I/O source. This prompts for an output format much like rendering does. Once that is done, the record window and the record monitor pop up.
The record window has discrete sections. While many parameters change depending on if the file has audio or video, the discrete sections are always the same.
- The output format area describes the format of the output file and the current position within it.
- The edit batch area lets you change parameters in the current batch.
- The transport controls start and stop recording different ways.
- The batch list displays all the defined batches.
- The confirmation area lets you determine how the output files are imported into the timeline and quit.
Recording in Cinelerra is organized around batches. A batch essentially defines a distinct output file for the recording. For now you can ignore the batch concept entirely and record merely by hitting the record button

The record button opens the current output file if it is not opened and writes captured data to it. Use the stop button to stop the recording. Recording can be resumed with the record button without erasing the file at this point. In the case of a video file, there is a single frame record button

When enough media is recorded, choose an insertion method from the Insertion Strategy menu and hit close.
19.1.2 Batch recording
Now we come to the concept of batches. Batches try to make the dumb I/O look more like a filesystem. Batches are traditionally used to divide tape into different programs and save the different programs as different files instead of recording straight through an entire tape. Because of the high cost of developing frame-accurate deck control mechanisms, the only use of batches now is recording different programs during different times of day. This is still useful for recording TV shows or time lapse movies as anyone who can not afford proper appliances knows.
The record window supports a list of batches and two recording modes: interactive and batch recording. Interactive recording happens when the record button is pressed. Interactive recording starts immediately and uses the current batch to determine everything except start time. By default, the current batch is configured to behave like tape.
Batch recording happens when the start button is pressed. In batch recording, the start time is the time the batch starts recording.
First, you will want to create some batches. Each batch has certain parameters and methods of adjustment.
- On
Determines whether the batch is included in batch recording operations. Click the list row under On to enable or disable batches.
- Path
It is the file the batch is going to be recorded to. The filename specified in the record dialog is the name of the first batch, to simplify interactive recording, but the filename may be changed in the record window for any batch in the edit batch area.
- News
Shows whether the file exists or not. This is a very important attribute since there is no confirmation dialog if the file exists. The first time you hit record, the file is opened. If the file exists at this point it is erased. News says File exists if it exists and OK if it does not. Every time you resume recording in the same batch, the news should say Open, indicating the file is already opened and will not be erased in the next record button press.
If you change out of the current batch after recording, the file is closed. Next time you change into the batch, the file will be erased.
- Start time
It is the 24 hour time of day the batch will start recording if in batch mode. The start time may become a time of tape and reel number if deck control is implemented but for now it is a time of day.
- Duration
This is the length of the batch. It only has meaning if the Mode of the batch is Timed. Once the recording length reaches duration the recording stops, whether in interactive or batch mode.
- Source
This has meaning only when the capturing hardware has multiple sources. Usually the source is a tuner channel or input. When the current batch finishes and the next batch begins recording, the source is changed to what the next batch is set to. This way multiple TV stations can be recorded at different times.
The record window has a notion of the current batch. The current batch is not the same as the batch which is highlighted in the batch list. The current batch text is colored red in the batch list. The highlighted batch is merely displayed in the edit batch section for editing.
By coloring the current batch red, any batch can be edited by highlighting it, without changing the batch to be recorded.
All recording operations take place in the current batch. If there are multiple batches, highlight the desired batch and hit activate to make it the current batch. If the start button is pressed, the current batch flashes to indicate it is waiting for the start time in batch mode. If the record button is pressed, the current batch is recorded immediately in interactive mode.
In batch and interactive recording modes, when the current batch finishes recording the next batch is activated and performed. All future recording is done in batch mode. When the first batch finishes, the next batch flashes until its start time is reached.
Interrupt either the batch or the interactive operation by hitting the stop button.
Finally there is the
19.1.3 Editing tuner information
Sometimes in the recording process and the configuration process, you will need to define and select tuner channels to either record or play back to. In the case of the Video4Linux and Buz recording drivers, tuner channels define the source. When the Buz driver is also used for playback, tuner channels define the destination.

The add operation brings up a channel editing box. The title of the channel appears in the channel list. The source of the channel is the entry in the physical tuner’s frequency table corresponding to the title.
Fine tuning in the channel edit dialog adjusts the physical frequency slightly if the driver supports it. The norm and frequency table together define which frequency table is selected for defining sources. If the device supports multiple inputs, the input menu selects these.
To sort channels, highlight the channel in the list and push move up or move down to move it.
Once channels are defined, the source item in the record window can be used to select channels for recording. The same channel selecting ability also exists in the record monitor window. Be aware channel selections in the record monitor window and the record window are stored in the current batch.
For some drivers an option to swap fields may be visible. These drivers do not get the field order right every time without human intervention. Toggle this to get the odd and even lines to record in the right order.19.2 Capturing using dvgrab
dvgrab is great and simple to use a command line tool to capture videos from a DV camcorder. When invoked it will automatically put your camera in play mode, and start storing the videos on your hard disk. Video files will be labeled sequentially, as: ‘001.avi’, ‘002.avi’ and so on.
To install dvgrab, use your distribution preferred installation mechanism (apt, rpm, deb, etc) or refer to the dvgrab webpage.
Capturing videos in four easy steps:
- Create a directory where you want the capture videos to be stored
- 'cd' to that directory
- Type: dvgrab --buffers 500 and RETURN
- Press CTRL-C to stop capturing video
The ‘--autosplit’ option is very useful. It splits scenes according to the timecode. However, that only works when grabbing from a DV camcorder. It will not work when grabbing from a analog/digital converter such as a Canopus ADVC110.
Read the dvgrab manual to get more information about dvgrab features.