Preliminary
The target of the prog. is to reroute audio streams in digital format on our personal computer, cut the streams using the silence algo and tag the final files converted in mp3 format.
To get this is necessary have a dreambox receiver 7000 or 7020 ( may be other models ),
one pc equipped with Ethernet connection
Main window (look screenshot)
after the CONNECT button is pressed, we have a situation like this, we got the info about the provider and the channel tuned, audio pid in hex and decimal format, if the grabber automatically recognise the bouquet then shows the selected genre ( in our example “dance” ).
At right we have the multigrab area, we can grab up to 3 streams in the same time plus the epg stream containing the info about the tracks.
To start one stream is very easy, just check the left checkbox, and the we can see the led light on the right side assuming the following colors:
red = disable
yellow = enabled
green = receiving data
more on the right the total bytes grabbed
From version 2.1 we got new options, on the right side we find 3 checkboxes, if set they active audio player of the selected stream ( until now only the device wave mapper is available ).
From version 2.2 we have the audio level indicator and the volume control for both left and right channels.
Also we got a new combo below the electronic track info guide, useful to grab to file one pid ( if you want to grab emm or ecm stream…). The file produced is stored into tracks folder.
Let’s have a close look to the settings window: (look screenshot)
At first we need to insert the folder containing the grabbed stream in the File Storage, then we have the “Skip first file” checkbox used to skip the first piece of stream when we start grab to avoid having one mp2 file not complete. The grab will start only after the first cut detection.
“Track n.” editbox is used to give the complete name to the file es. Track_0001 where the number is got from the editbox.
“No cut (s) is the time after one cut that the system is forced to be blind to other cut signal, for example can happen for certain songs at the beginning the amplitude is very low or we can have some false silence situation ( valid only for standard cut mode and rename cut mode ).
“Silence cycles” represents the exact occurences of bytes ( for stereo 16 bit is a couple of bytes ) that have value = zero to understand that we are in a silence situation. Of course this is not enough, we must add some filter to avoid as much as possible some false silence detection, and for this we have other 8 fields called “Last chunk threshold”.
Now i think we need to spend some words to explain the theory for understand the meaning of those fields…
We start from MP2 frames composed by one header and data, and for example in our case the data length is 480 bytes. I feed the MPEG decoder with those data and of course I will get much more PCM bytes because the MP2 is compressed. Ok, I take 8192 bytes of raw PCM data as output from decoder and I call this “chunk” . In the sw every chunk is converted in one value that represent the average, and at the end of the conversion function every last chunk is shifted in one array containg 8 previous average values. So in any moments we can have the availability of last 8 chunk value.
These values are used when we are in the silence moment ( after “Num. of silence recognition cycles” ) and I check that every last chunk ( from 0 to 7 ) is below its threshold ( editbox values from 0 to -7 ), if every condition is satisfied the I launch the cut signal.
Easy!! Or not? Yes it’s easy in words, but in the development of the sw be sure that it was not easy ehm….
Talking now about which kind of cut we like to use… first the STANDARD cut, like in the past, for every silence we get a different track file, the ADVANCED CUT MODE, we use the new feature with the name of the song to detect the real cut, the RENAME CUT MODE, this is like the standard mode, but the program renames immediately the track file with the current info of the song, if the file is already present the rename is skipped, the last mode ADVANCED RENAME CUT MODE is the ADVANCED CUT MODE used in conjunction with the RENAME CUT MODE.
Transcoding and tagging , the first one is to set up the mp2->mp3 transcoder with the parameter we want, the second one is to tag the file with the preferred sequence of information field, for example you can choose first the artist then the title or the album and so on..
From the version 2.1 we got a new parameter, used to force a delay in the change titol track event, but only for mce sky italy, because sometime titol changes before the effective end of the track.
From version 2.2 the http authentication is completely automatic, so is necessary to include the user name and the password in the right fields.
New from version 2.3, the capability of rebroadcast all the 3 stream over tcp using http protocol, we have for this 3 new fields representing the tcp ports assigned to the streamer ( 1,2,3). The protocol used is TCP Unicast.
Also we have the PES analizer window like in the old version of the program.
From version 2.4 we have two new parameters, the first “ MCE Mode” is to enable the digital detection of the end of one track contained in the mp2 frames header received, the second “Silence level” is for define a level threshold of the audio PCM bytes to start the silence detection routine.
Last important new feature is the support of pci dvb card like skystar for example, to use it is needed the plugin dgrabber server and put the ip address 127.0.0.1 ( local host ), that’s all!!
Note: at the moment is possible use only constant bitrate in the transcoder.
Provider compatible are Xtramusic 13 and 19 east, Sky italy 13 east and Premiere 19 east.
This is all for now…. Have a nice grab !!!
Oldman