Em Fri, 4 Jan 2013 00:39:25 +0530 Manu Abraham <abraham.manu@xxxxxxxxx> escreveu: > Hi Antti, > > On Thu, Jan 3, 2013 at 9:04 PM, Antti Palosaari <crope@xxxxxx> wrote: > > On 01/01/2013 06:48 PM, Manu Abraham wrote: > >> > >> On Tue, Jan 1, 2013 at 8:30 PM, Mauro Carvalho Chehab > >> <mchehab@xxxxxxxxxx> wrote: > >> > >>> [RFCv4] dvb: Add DVBv5 properties for quality parameters > >>> > >>> The DVBv3 quality parameters are limited on several ways: > >>> - Doesn't provide any way to indicate the used measure; > >>> - Userspace need to guess how to calculate the measure; > >>> - Only a limited set of stats are supported; > >>> - Doesn't provide QoS measure for the OFDM TPS/TMCC > >>> carriers, used to detect the network parameters for > >>> DVB-T/ISDB-T; > >>> - Can't be called in a way to require them to be filled > >>> all at once (atomic reads from the hardware), with may > >>> cause troubles on interpreting them on userspace; > >>> - On some OFDM delivery systems, the carriers can be > >>> independently modulated, having different properties. > >>> Currently, there's no way to report per-layer stats; > >> > >> > >> per layer stats is a mythical bird, nothing of that sort does exist. If > >> some > >> driver states that it is simply due to lack of knowledge at the coding > >> side. > >> > >> ISDB-T uses hierarchial modulation, just like DVB-S2 or DVB-T2 > > > > > > Manu, you confused now two concept (which are aimed to resolve same real > > life problem) - hierarchical coding and multiple transport stream. Both are > > quite similar on lower level of radio channel, but differs on upper levels. > > > > Hierarchical is a little bit weird baby as it remuxes those lower lever > > radio channels (called layers in case of ISDB-T) to one single mux! > > That is not really correct. There is one single OFDM channel, the layers > are processed via hierarchial separation. Stuffing exists, to maintain > constant rate. > > http://farm9.staticflickr.com/8077/8343296328_e1e375b519_b_d.jpg > > When rate is constant within the same channel.. > (The only case what I can think parameters could be different with a > constant rate, > is that stuffing frames are unaccounted for. Most likely a bug ?) What did you smoke? That picture has nothing to do with ISDB! ISDB not only does hierarchical split. It also splits the OFDM carriers into 3 layers, each layer with its own modulation, guard interval, inner FEC, etc. Each of those layers behave as an independent channel, providing different bit rates. Cheers, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
