SdRecorder 2.00SdRecorder 2.00Users guide
by
Keith Rubow
SdRecorder records sound from the audio input jack of your computer directly to MP3 files. While SdRecorder was designed with features to make it easy to record live square dances, it can be used for recording any audio, such as converting record albums or tapes to MP3 files.
To install SdPlayer on a Windows computer it is necessary to install two different items.
Source files for SdRecorder are available as a zip file called SdRecorderv.vv.zip.
SdRecorder is distributed as a Debian package file called sdrecorder_v.vv_i386.deb, where v.vv is the program version number. Simply double-click the package file to install it, or open the package file with your package manager. The SdRecorder software is installed in /usr/share/sdrecorder. A script file to launch SdRecorder is installed in /usr/bin. The initial default configuration "ini" file is installed in /usr/share/xdg/krubow, and any user configuration settings are saved in ~/.config/krubow. An application menu entry is automatically created, typically under Sound and Video (or something similar). Your package manager will automatically install the required LAME encoder and Qt runtime libraries if these are not already installed on your system. Source files for SdRecorder are available as a zip file called SdRecorderv.vv.zip.
SdRecorder may be uninstalled using your package manager.
SdRecorder is designed to be as easy to use as possible, while still giving you access to all the different options you need. Recording is done in a few easy steps.
Step 1, go to settings (under the Options menu) and select your sound card, input parameters, sound activated recording options, "Save To" folder, and MP3 file compression settings. These settings are saved, and usually do not need to be changed for future recording sessions.
Step 2, on the main window, enter any ID3v1 tags that you wish to be included in your files, as well as the filename for saving your MP3 files. SdRecorder will automatically append a number to the end of the file name, numbering the files sequentially. Files will be saved to the "Save To" folder you selected in settings. The ID3v1 tags and the filename are also saved for your convenience.
Step 3, click the Record button to bring up the recording window. This window displays the recording level meters. There will be a level meter and a peak meter for each of your recording channels (left and right). Only the left channel meters are displayed if your input is set to mono. There is also a slider to adjust the recording level. The recording level you ad set is saved for the next time you launch SdRecorder. At this point simply click the Start Recording button to start your recording, and click Stop Recording to stop recording. You may start and stop recording as many times as you like. Each recording will be saved to a separate file. If you are using sound activated recording, recording will start and stop automatically as the sound starts and stops. While recording is in process, the duration of the recording and the peak level found (in dB) during the recording are displayed in the lower left corner of the Record window. This information will stay there until it is reset when a new recording is started. The level information is useful to check if the recording level is set properly.
Step 4, click the Exit button to exit the recording window. This will automatically stop any recording that was in progress.
There is only one entry on the Options menu. It is Settings to open the Settings dialog box. Use the Settings dialog box to select all of your recording options. See the Settings section below for details.
There are two entries on the Help menu.
Help will display the SdRecorder help file in your browser.
About will display the About dialog box, which shows the program version number and the version of the LAME MP3 encoder being used.
Select Options->Settings from the menu to display the Settings dialog box. The following settings are available:
Record From: Use the drop down list to select the sound card you wish to use for your audio input. Selecting "default" will use the default audio input device on your computer.
Sample Rate: Use the drop down list to select the desired sample rate for capturing audio from your sound card. The sample rate must be set to at least double the bandwidth (i.e. highest frequency) you wish to capture. A sample rate of 44100 is standard for HiFi quality (20KHz bandwidth). A Sample rate of 22050 gives quality comparable to AM radio (10KHz bandwidth). Lower sample rates may be used for voice-only recordings, while sample rates higher than 44100 are rarely needed. Not all sound cards will support all possible sample rates.
Channels: Use the drop down list to select 1 channel for mono input, or 2 channels for stereo input. Note that this selects the number of channels for your sound input. This does not need to be the same as the number of channels for your MP3 output file, although it usually is. SdRecorder allows recording stereo input to mono output (it will combine the left and right channels together into one output channel), or mono input to stereo output (the input channel will be duplicated on both output channels). Recording stereo input to mono output can be useful, though recording mono input to stereo output is hardly ever needed.
Sound Activated: Check this box to enable the sound activated recording feature. Clear the box to disable sound activated recording if you wish to start and stop the recordings manually.
Start Level/Start Time: Set these to determine the sound level and time to automatically start recording if sound activated recording is enabled. The sound level must be above Start Level (set as 0-100) for Start Time (set in seconds) for recording to start automatically.
Stop Level/Stop Time: Set these to determine the sound level and time to automatically stop recording if sound activated recording is enabled. The sound level must be below Stop Level (set as 0-100) for Stop Time (set in seconds) for recording to stop automatically.
Save To: Click the Save To button to select the folder where the MP3 output files will be saved. Alternatively, type the path to the output folder in the the text entry box.
MP3 Output settings are used to select the options for the MP3 output files.
Channels: Use the drop down list to select the channels for the MP3 output file. This may be set to Mono, Stereo or Joint Stereo. Joint Stereo is generally preferable to Stereo, as it takes advantage of the similarity of the left and right channels to encode the stereo data more efficiently.
Encoding: Use the drop down list to select the encoding method to be used for the MP3 output files. It may be set to Constant Bit Rate (CBR), Average Bit Rate (ABR) or Variable Bit Rate (VBR). CBR works better for sound players that need to seek forward and back to different places in the MP3 file, while VBR can produce smaller MP3 files.
Bitrate: Use the drop down list to select the bitrate of the output file. As a general rule of thumb, bitrates of 128 to 192 Kbps are used with stereo files at a sample rate of 44100 Hz. Bitrates of 64 to 96 Kbps are used with mono files at a sample rate of 44100 Hz. Bitrates of 32 to 48 Kbps are used with mono files at a sample rate of 22050 Hz. Lower bitrates can be used with lower quality voice-only recordings at lower sample rates. Higher bitrates can be used to give the best quality MP3 files nearly indistinguishable from uncompressed audio files.
Frequency: Use the drop down list to select the sample rate of the MP3 output file. This is usually set to the same as the sound card sample rate, but could be set lower to generate smaller lower quality output files. Setting the MP3 file sample rate higher than the sound card sample rate will not improve the quality or bandwidth of the sound.
Quality: Use the drop down list to select the quality and speed of the software algorithms used to generate the MP3 files. Set to Low to sacrifice some sound quality for faster conversion speed. Set to Medium to get good sound quality with average conversion speed. Set to High to get slightly better sound quality at the expense of slower conversion speed. Medium is a good setting to use for most recordings.
SdRecorder can optionally save ID3v1 tags to your MP3 output files. The Artist, Album, Year and Comment fields on the main window are used to enter any desired ID3v1 tags. The track number will be set to the sequential output file number (starting at 1), and the genre will be set to "none". If no data is entered in any of the ID3v1 tag fields, then no tags will be written to the MP3 files.
The File Name field on the main window determines the name of your output file(s). SdRecorder will automatically append a number to the end of the file name to make each output file name unique. For example, setting the File Name to "myfile" will result in output files names "myfile001.mp3", "myfile002.mp3", etc. These files will be saved to the "Save To" folder specified in the Settings dialog box.
Note that SdRecorder is very careful to NEVER overwrite any existing MP3 files. For example, if "myfile001.mp3", "myfile002.mp3" and "myfile004.mp3" already exist, SdRecorder will generate files named "myfile003.mp3", "myfile005.mp3", "myfile006.mp3" etc.
Sound Activation can be enabled in settings to allow SdRecorder to automatically start and stop recording as the sound input starts and stops. Recording starts when the input sound level is above Start Level for Start Time seconds. Start Level is specified as 0-100, where 100 actually represents a VU meter reading of 50 percent of full scale, and Start Time is in seconds to a resolution of .05 seconds. Recording stops when the input sound level is below Stop Level for Stop Time seconds. Once again, Stop Level is specified as 0-100, where 100 actually represents a VU meter reading of 50 percent of full scale, and Stop Time is specified in seconds to a resolution of .05 seconds. The Stop Level should be set to a level equal to or less than the Start Level. Usually the Start Level and Stop Level will be set to the same level. As a general rule the Start Level should be set as low as possible while avoiding false starting from background noise. Stop Time should be set long enough to avoid stopping prematurely during short quiet times. When recording square dances, I recommend a Stop Time of at least 10 seconds, with 20 seconds or more sometimes working better. A long Stop Time just results in more silence at the end of the file, which can easily be edited off later with your favorite audio editor (such as MP3DirectCut or Audacity).
To assist in determining an appropriate level for sound activated recording, click on the word "level" just to the right of the left channel VU meter on the Record window. This changes "level" into a real-time display of the sound level that will be used for sound activated recording. This enables you to see what the background noise level is when no sound is present. It also lets you see the actual level of a sound that you would like to trigger the sound activated recording. For example, if the background noise level is reading 0% to 1% with no sound present, but goes up to 4% or more with a soft sound that you would like to trigger recording, then setting the Start Level and Stop Level to 2 or 3 would work well. Setting Start Level to 1 would probably result in false triggering on the background noise. However, if the background noise level consistently reads 0, then you could set the Start Level as low as 1 to trigger recording with a very low level sound. Click the displayed level again to turn this feature off and display the word "level".
When Sound Activation is used with stereo input, SdRecorder uses the higher of the left and right channel sound levels to determine when recording should start and stop. In this way Sound Activation will work properly even if only one channel has sound.
When Sound Activation is used it is still possible to start and stop recordings manually using the Start Recording/Stop Recording button.
The Recording window includes recording level meters for both the left and right input channels. Only the left channel meters are displayed if the input is set to mono.
Each channel has a sound level meter that shows the instantaneous sound level (similar to a standard VU meter), as well as a peak level meter. These meters show the sound level whether recording is active or not. The peak meter shows the instantaneous peak level of the audio input waveform over each 1/2 second interval. The peak meter is updated each 1/2 second, and holds the reading until the next update.
The peak level meters are most useful for setting the sound input level for recording. Ideally, the sound input should never be allowed to clip. As long as the peak meters do not reach full scale, there will be no clipping. It is best to set the recording level such that the peak meters reach about 50% of full scale.
SdRecorder provides a recording level control on the Record window, just below the level meters. The recording level is displayed as a number 0-100 to the left of the recording level control, and as a level in dB to the right of the recording level control. This makes it very easy to adjust your recording level. The sound level should be set so the peak level meter never reaches full scale. Ideally the peak meter should reach a maximum of about 50% of full scale. This is important to maintain some "headroom" to avoid clipping should the sound sometimes peak to an unusually high level. It is always better to record at a level a little on the low side rather than a level that is too high. An output file with a lower level can always be normalized to a higher volume later. A file that is recorded at too high a level and experiences clipping cannot be fixed later. Clipping simply cannot be undone.
If the recording level control on the Record window does not function, it will be necessary to use the recording level control provided by your operating system.