[vdr] Re: DVD-AC3-Playback

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Stephan Schreiber wrote:
> 
> Hello Klaus,
> 
> > Can somebody please explicitly verify whether or not Andreas'
> > suggested modification
> >
> >            int written = b[8] + 9; // skips the PES header
> >            if ((b[written] & 0xF0) == 0x80)
> >               written += 4;
> >
> > actually works for DVDs _and_ DVB recordings? If it doesn't, I'll have to
> > add a flag to distinguish between DVD and DVB (which I would like
> > to avoid...).
> 
> I did yesterday, and Uwe confirmed my observations.
> Andreas' modification does not work with my AC3 VDR recordings.
> Some frames seem to match the condition
> >            if ((b[written] & 0xF0) == 0x80)
> so I get stutterings and my amplifier switches back to PCM mode every few
> seconds.
> It stays in 3/2.1 mode most of the time however.
> 
> The DVD's I tested however work perfectly ever since.
> 
> That flag you mentioned seems not to be an idea _that_ bad after all, if
> maybe a little "ugly"....

Well, then just to make sure I don't break anything else, can you please
try this modification:

--- dvbapi.c    2001/11/24 14:45:58
+++ dvbapi.c    2001/11/25 16:38:09
@@ -710,6 +710,7 @@
   int readIndex, writeIndex;
   bool canDoTrickMode;
   bool canToggleAudioTrack;
+  bool skipAC3bytes;
   uchar audioTrack;
   void TrickSpeed(int Increment);
   virtual void Empty(bool Block = false);
@@ -752,6 +753,7 @@
   readIndex = writeIndex = -1;
   canDoTrickMode = false;
   canToggleAudioTrack = false;
+  skipAC3bytes = false;
   audioTrack = 0xC0;
   if (cDvbApi::AudioCommand()) {
      if (!dolbyDev.Open(cDvbApi::AudioCommand(), "w"))
@@ -769,7 +771,7 @@
      if (b[0] == 0x00 && b[1] == 0x00 && b[2] == 0x01) {
         if (b[3] == 0xBD) { // dolby
            int l = b[4] * 256 + b[5] + 6;
-           int written = b[8] + 9; // skips the PES header
+           int written = b[8] + (skipAC3bytes ? 13 : 9); // skips the PES header
            int n = min(l - written, MaxLength);
            while (n > 0) {
                  int w = fwrite(&b[written], 1, n, dolbyDev);
@@ -1545,6 +1547,7 @@
   canToggleAudioTrack = true;//XXX determine from cDVD!
   data = new uchar[1024 * DVD_VIDEO_LB_LEN];
   canDoTrickMode = true;
+  skipAC3bytes = true;
   dvbApi->SetModeReplay();
   Start();
 }


Maybe the line numbers don't match exactly, but this is such a small
modification that you should even be able to do it manually.

Can you confirm that this now replays DVD _and_ DVB external AC3 sound
correctly?

Klaus
-- 
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Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
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