harriscs wrote:
mpeg2 is lossless mode for digital TV
Yes, I had thought that maybe what I was asking has to do only with analogue sources. (/quote]Maybe you're refering to Huffyuv lossless codec, that exists on most windows systems.
In short, NO.
That's not, what we're talking about.
DVB transmissions always are effecitvely but also lossy compressed.
Video standard is MPEG2, for normal SDTV.
But SiLencer talked about lossless recording.
That indeed means, streams are simply copied into a file container, nothing but that.
harriscs wrote:But how you explain that 1 minute of recording with "Technisat TV Center" produces a file of 30 MB and with ProgDVB only 15 MB? Is there any difference in quality?
Not between the DVB applications, but simply between stations and transmissions.
Stations have to pay for bandwidth.
Providers decide, how many stations to squeeze trough a limited transponder data rate at a time.
Video streams are coded at variable bit rates.
Those depend on content complexity - (semi)automatically shifting rssources between stations on the same transponder on uplink multiplexing - and a preselected priority between those.
harriscs wrote:Do you mean that ProgDVB "receives" or "copies" the video and audio streams exactly as they are being sent and it just selects a container to store them? In other words, it maintains the original resolution, bitrate, codecs etc?
Exactly.
But providers / uplinkers normally use professional hardware codecs, not to be compared with what's available for us.
harriscs wrote:but not play compatible with general media players.
Yes, I can verify that... I tried to capture in pva and I ascertained that the resulting file could not be played in any player (including VLC)! I downloaded the RadLight's pva splitter, but despite the full graph in GraphEdit, I was having a distorted image in my playback. Possibly the problem is in the DirectShow splitter? I don't know...
Try PVAStrumento or ProjectX.
PVA is a proprietary format of TechnoTrend, created ages ago for SS1 / premium cards, that also provide special hardware support for it, for extremely slow CPUs (200 MHz class). That's obsolete and not even meant to be compatible with non-DVB applications.
You'd have to extract the streams and pack them into a general use container like .mpg for later use.
harriscs wrote:though still not perfect without remuxing or some other post processsing.
I am going to re-mux with MKVToolnix, because I think that matroska is by far the best file container. But I need smaller filesizes, so I will compress a little. I hope that the resulting file will be OK. BTW, how you compress an audio stream of MP3 @128 Kbps? What will be the quality of the final result if I select eg Vorbis @64 Kbps?
...this pretty much depends on content, recompressing method, tool quality, stereo mode (joint stereo need a bit less data), VBR and on-the-fly or single or two pass..
And of course professional soft- or even hardware should give better results than home brew stuff, normally...
harriscs wrote:Keep in mind, real time transcoding would need extremely high CPU power.
I am not interested in real-time transcoding. I want the best possible capture (regardless of the filesize) in the first step and in a second step I want to compress in the way I want (codecs, bitrates etc), like I was doing with my analogue TV captures.
Sure.
If you think HDD (or DVD) space still to expensive these days...
harriscs wrote:BTW, ProgDVB, like other DVB soft, won't handle any analogue sources.
I know that. I never said or asked something like that.
See above:
harriscs wrote:I am not sure if this is only for analog sources
harriscs wrote:Yes, I had thought that maybe what I was asking has to do only with analogue sources.
