Data Formats
TV and audio DVB broadcasting currently uses a family of formats called MPEG2. The data is packaged into logical streams. The raw data received from a satellite transponder is a TS (Transport Stream), sometimes called a bouquet because a TS usually contains several TV and radio channels. The DVB drivers and ZapDvb reduce this to a single channel and convert the data of a TV channel to a PES (Packetized Elementary Stream). Most Linux players like MPlayer and Xine can read PES data. To record a TV channel, it would be sufficient to capture the PES stream to a file.
Things are slightly different for radio channels, as most audio players do not understand a PES. For this reason ZapDvb extracts an ES (Elementary Stream) from radio channels. The (sub-)format of this stream is Layer II, therefore the file extension .mp2 is used. Some audio players understand this format. But as you noticed, audio is not broadcasted in mp3 (Layer III) format! ZapDvb supports Lame (if installed). But using mp3 is not recommended, you need a license to use it. This is why the public domain Ogg Vorbis format is recommended and the supported encoder is sox (very common, comes with SuSE 9.1 for example).
Foreground and Background Recording
ZapDvb offers foreground and background recording. One will use foreground recording spontaneously, e.g. while a TV or radio channel is playing the data stream can be captured to disk. The resulting disk files can later be edited with the MPEG editor LINK ME. A nice feature is that you can pause the player whenever you want (to answer a ringing phone for example) and ZapDvb automatically enters capture mode. Background recording is usually a planned action, you will schedule a recording to occur once at a given time (timed recording) or to run repeatedly at given dates (periodic recording). The following text sections will explain things in more detail.
Compared to other solutions, ZapDvb offers more flexibility and a deeper integration. When background recording is used, the recordings run as batch jobs managed via the standard Linux programs atd or cron. No user needs to be logged in and no desktop program needs to run. Together with the 2.6 kernel the PC remains usable for other activities. It is even recommended to build a (video) server with one or more DVB cards. An important example of integration is the automatic deletion of recorded data. At first sight this seems odd, but imagine that your server would be configured to automatically record the evening news or your favorate series. Here automatic deletion prevents the hard disk(s) from overflowing: you will usually not like to watch the evening news a week later, so things that you don't take care off can be automatically deleted after a few days.
An Important Warning to Users
Specially if you use it in settop box mode (connected to the TV set in your living room) ZapDvb may change your habits. After a while watching life TV may appear strange to you. You will save enormous amounts of time by no longer being tortured with commercials or trailers - and no more zapping! The ultimate feature is periodic recording followed by automatic deletion - no human intervention required. You will never have the feeling that you miss something on TV when it gets automatically recorded. And you will save time as you will realize that most TV stuff is so unimportant that you will never want to watch the recorded data, this is where automatic deletion takes care of it. Believe me, try it!
The README files contain some information on this subject.
The README files contain some information on this subject.
Currently discussed in the Editor description.