[opus] Ogg Format

[Amit Ashara]

Hello Jean-Marc,

So for the moment we can assume that this method is also OK to use?

On Embedded Systems, both SRAM and Flash can be a restricting factor
besides the compute time. To optimize the utilization of embedded
resources, may I suggest a simplification of the Ogg-Opus format and can
this be considered by the Opus org and IETF as an addition?

Regards
Amit

On Wed, May 11, 2016 at 12:09 PM, Jean-Marc Valin <jmvalin at jmvalin.ca>
wrote:

> On 05/11/2016 12:35 PM, Amit Ashara wrote:
> > I ran the opusenc.exe on a wave file and checked the OpusTag section. My
> > concern is on Total Segment Size being >> than the actual data being
> > put. Is this just an example of implementation or does a size of 764
> > BYTES kept as a place holder for putting more data?
>
> Yes, opusenc does reserve some space in the header so that tags can
> later be modified "in place", without having to rewrite the entire file.
>
>         Jean-Marc
>
>
> > 4f 67 67 53 = Oggs
> > 00 = Version
> > 00 = Header
> > 00 00 00 00 00 00 00 00 = Granule Position
> > a5 73 00 00 = Bit Stream Serial Number
> > 01 00 00 00 = Page Sequence Numner
> > 90 a9 36 42 = Checksum
> > 03 = Page Segments
> > ff ff fe = Each Segment Size (TOTAL SIZE IS 764 BYTES)
> > 4f 70 75 73 54 61 67 73 = OpusTags
> > 0b 00 00 00 = Vendor String Length of 11
> > 6c 69 62 6f 70 75 73 20 31 2e 31 = "libopus 1.1"
> > 03 00 00 00 = User Comment List Length of 3
> > 25 00 00 00 = User Comment #0 String Length of 37
> > 45 4e 43 4f 44 45 52 3d 6f 70 75 73 65 6e 63 20 66 72 6f 6d 20 6f 70 75
> > 73 2d 74 6f 6f 6c 73 20 30 2e 31 2e 39 = "ENCODER=opusenc from
> > opus-tools 0.1.9"
> > 0a 00 00 00 = User Comment #1 String Length of 10
> > 74 69 74 6c 65 3d 48 4f 4c 41 = "title=HOLA"
> > 1e 00 00 00 = User Comment #2 String Length of 30
> > 45 4e 43 4f 44 45 52 5f 4f 50 54 49 4f 4e 53 3d 2d 2d 6d 61 78 2d 64 65
> > 6c 61 79 20 32 30 = "ENCODER_OPTIONS=--max-delay 20"
> > 00 00 00... ALL THE WAY TO THE NEXT Oggs Container
> >
> > Regards
> > Amit
> >
> > On Tue, May 10, 2016 at 10:47 PM, Ralph Giles <giles at thaumas.net
> > <mailto:giles at thaumas.net>> wrote:
> >
> >     On 10/05/16 02:37 PM, Amit Ashara wrote:
> >
> >     > Is there a format document on the OpusTag structure? Search always
> shows
> >     > up Vorbis but not Opus.
> >
> >     The basic format is shared with Vorbis, but the 'magic signature' is
> >     different ('OpusTags' instead of '0x05vorbis') and vorbis puts a 0x01
> >     value in an extra byte after the last tag.
> >
> >     The OpusTag packet layout is described in
> >     https://tools.ietf.org/html/rfc7845.html#section-5.2
> >
> >     Common tag names used for interoperability are described in the
> Vorbis
> >     documentation. See https://www.xiph.org/vorbis/doc/v-comment.html
> >     There are more extensive tag lists on some other sites.
> >
> >
> >
> >
> > _______________________________________________
> > opus mailing list
> > opus at xiph.org
> > http://lists.xiph.org/mailman/listinfo/opus
> >
>
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