[vdr] Re: vdr cuts recordings with ugly artifacts at cutting-points

["Dr. Werner Fink" <werner@suse.de>]

On Tue, Apr 15, 2003 at 10:03:06AM +0000, Stefan Huelswitt wrote:
> 
> OK, find the attached patch which sets the broken link flag on
> every "cuttIn" frame. I did only a short test. It still cuts
> fine and it seems that the decoder honors the broken link flag.
> The cutting points are smoother.
> 
> The problem of missing audio packets due to audio-video delay
> still has to be solved.

Maybe a read ahead buffer could be used to filter out all
audio/ac3 frame with the formular

          if (video_PTS >= none_video_PTS)
              include audio_or_ac3
          else
              skip audio_or_ac3

this would require that the last few and next few
none video packages around the cutting point must
be buffered for comparision.

         Werner

> diff -urN vdr-1.1.27-orig/cutter.c vdr-1.1.27-cutter/cutter.c
> --- vdr-1.1.27-orig/cutter.c	2002-08-11 13:09:23.000000000 +0200
> +++ vdr-1.1.27-cutter/cutter.c	2003-04-15 10:53:56.000000000 +0200
> @@ -23,6 +23,8 @@
>    cFileName *fromFileName, *toFileName;
>    cIndexFile *fromIndex, *toIndex;
>    cMarks fromMarks, toMarks;
> +  //
> +  void BrokenLink(uchar *data, int len);
>  protected:
>    virtual void Action(void);
>  public:
> @@ -60,6 +62,26 @@
>    delete toIndex;
>  }
>  
> +void cCuttingThread::BrokenLink(uchar *data, int len)
> +{
> +  if(data[0]==0 && data[1]==0 && data[2]==1 && (data[3]&0xE0)==0xE0) {
> +    int index=9+data[8]; // skip video packet header
> +    for( ; index<len ; index++) {
> +      if(data[index]==0 && data[index+1]==0 && data[index+2]==1 && data[index+3]==0xB8) {
> +        if(!(data[index+7]&0x40)) {
> +          data[index+7] |= 0x20;
> +          printf("setting broken link flag in CuttIn GOP\n");
> +          }
> +        else
> +          printf("cuttIn GOP is closed\n");
> +        return;
> +        }
> +      }
> +    printf("no GOP header found in cuttIn video packet\n");
> +    }
> +  else printf("no video packet in cuttIn frame\n");
> +}
> +
>  void cCuttingThread::Action(void)
>  {
>    dsyslog("video cutting thread started (pid=%d)", getpid());
> @@ -77,6 +99,7 @@
>       toMarks.Add(0);
>       toMarks.Save();
>       uchar buffer[MAXFRAMESIZE];
> +     bool cuttIn = true;
>       while (active) {
>             uchar FileNumber;
>             int FileOffset, Length;
> @@ -126,6 +149,11 @@
>                   FileSize = 0;
>                   }
>                LastIFrame = 0;
> +
> +              if(cuttIn) {
> +                BrokenLink(buffer, Length);
> +                cuttIn=false;
> +                }
>                }
>             if (safe_write(toFile, buffer, Length) < 0) {
>                error = "safe_write";
> @@ -151,6 +179,7 @@
>                   Index = Mark->position;
>                   Mark = fromMarks.Next(Mark);
>                   CurrentFileNumber = 0; // triggers SetOffset before reading next frame
> +                 cuttIn = true;
>                   if (Setup.SplitEditedFiles) {
>                      toFile = toFileName->NextFile();
>                      if (toFile < 0) {
> 
> 
> -- 
> Stefan Huelswitt
> huels@iname.com  | http://home.pages.de/~nathan


-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe vdr" as subject.