[FFmpeg-devel] [PATCH] Missing Theora 3.2.1 granule support

[Måns Rullgård]

Henrik Gulbrandsen <henrik at gulbra.net> writes:

> Given the modified granule semantics for Theora bitstreams, which was
> mentioned in my previous email, the theora_gptopts function needs to
> change if it should still map from granule positions to PTS when the
> bitstream version is 3.2.1 or higher.
>
> I haven't actually tested this on a new bitstream, but with some good
> code review and a little luck, this may actually work as intended :-)
>
> /Henrik
>
>
> Index: libavformat/oggparsetheora.c
> ===================================================================
> --- libavformat/oggparsetheora.c	(revision 12887)
> +++ libavformat/oggparsetheora.c	(working copy)
> @@ -29,6 +29,7 @@
>  #include "oggdec.h"
>  
>  typedef struct theora_params {
> +    unsigned version;
>      int gpshift;
>      int gpmask;
>  } theora_params_t;
> @@ -95,6 +96,7 @@ theora_header (AVFormatContext * s, int 
>          if (version >= 0x304000)
>              skip_bits(&gb, 2);
>  
> +        thp->version = version;
>          thp->gpshift = get_bits(&gb, 5);
>          thp->gpmask = (1 << thp->gpshift) - 1;
>  
> @@ -124,6 +126,11 @@ theora_gptopts(AVFormatContext *ctx, int
>      uint64_t iframe = gp >> thp->gpshift;
>      uint64_t pframe = gp & thp->gpmask;
>  
> +    // We want PTS (beginning of display interval)
> +    // rather than the count of frames seen so far.
> +    if (thp->version >= 0x030201 && iframe > 0)
> +        iframe--;

What if iframe == 0?

-- 
M?ns Rullg?rd
mans at mansr.com