r19126 - trunk/DOCS/tech/nut.txt
Author: michael Date: Mon Jul 17 01:47:12 2006 New Revision: 19126 Modified: trunk/DOCS/tech/nut.txt Log: clarify H.264 global header format Modified: trunk/DOCS/tech/nut.txt ============================================================================== --- trunk/DOCS/tech/nut.txt (original) +++ trunk/DOCS/tech/nut.txt Mon Jul 17 01:47:12 2006 @@ -525,6 +525,8 @@ for(i=0; i<number_of_headers; i++) header[i] Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes) frame_code the meaning of this byte is stored in the main header
michael <subversion@mplayerhq.hu> writes:
Author: michael Date: Mon Jul 17 01:47:12 2006 New Revision: 19126
Modified: trunk/DOCS/tech/nut.txt
Log: clarify H.264 global header format
Modified: trunk/DOCS/tech/nut.txt ============================================================================== --- trunk/DOCS/tech/nut.txt (original) +++ trunk/DOCS/tech/nut.txt Mon Jul 17 01:47:12 2006 @@ -525,6 +525,8 @@ for(i=0; i<number_of_headers; i++) header[i] Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes)
It's actually 00 00 00 01 (four bytes) for the NAL units that we're dealing with here. To make this unambiguous, I would change the text to read For H.264 the format MUST be that specified in ITU-T Rec. H.264 Annex B Byte stream format. -- Måns Rullgård mru@inprovide.com
Hi On Mon, Jul 17, 2006 at 01:09:37AM +0100, Måns Rullgård wrote:
michael <subversion@mplayerhq.hu> writes:
Author: michael Date: Mon Jul 17 01:47:12 2006 New Revision: 19126
Modified: trunk/DOCS/tech/nut.txt
Log: clarify H.264 global header format
Modified: trunk/DOCS/tech/nut.txt ============================================================================== --- trunk/DOCS/tech/nut.txt (original) +++ trunk/DOCS/tech/nut.txt Mon Jul 17 01:47:12 2006 @@ -525,6 +525,8 @@ for(i=0; i<number_of_headers; i++) header[i] Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes)
It's actually 00 00 00 01 (four bytes) for the NAL units that we're dealing with here. To make this unambiguous, I would change the text to read
For H.264 the format MUST be that specified in ITU-T Rec. H.264 Annex B Byte stream format.
agree, but we should still mention that its 0 0 0 1 + NAL as not every reader of nut.txt will have (or want) every spec of every codec ... [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB In the past you could go to a library and read, borrow or copy any book Today you'd get arrested for mere telling someone where the library is
Michael Niedermayer <michaelni@gmx.at> writes:
Hi
On Mon, Jul 17, 2006 at 01:09:37AM +0100, Måns Rullgård wrote:
michael <subversion@mplayerhq.hu> writes:
Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes)
It's actually 00 00 00 01 (four bytes) for the NAL units that we're dealing with here. To make this unambiguous, I would change the text to read
For H.264 the format MUST be that specified in ITU-T Rec. H.264 Annex B Byte stream format.
agree, but we should still mention that its 0 0 0 1 + NAL as not every reader of nut.txt will have (or want) every spec of every codec ...
Fine by me. I just want the proper reference included for those that do have the document. -- Måns Rullgård mru@inprovide.com
Måns Rullgård wrote:
Michael Niedermayer <michaelni@gmx.at> writes:
Hi
On Mon, Jul 17, 2006 at 01:09:37AM +0100, Måns Rullgård wrote:
michael <subversion@mplayerhq.hu> writes:
Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes)
It's actually 00 00 00 01 (four bytes) for the NAL units that we're dealing with here. To make this unambiguous, I would change the text to read
For H.264 the format MUST be that specified in ITU-T Rec. H.264 Annex B Byte stream format. agree, but we should still mention that its 0 0 0 1 + NAL as not every reader of nut.txt will have (or want) every spec of every codec ...
Fine by me. I just want the proper reference included for those that do have the document.
Actually, some NALs (PPS, SPS ?) can start with 00 00 01 IIRC. -- Baptiste COUDURIER GnuPG Key Id: 0x5C1ABAAA SMARTJOG S.A. http://www.smartjog.com Key fingerprint 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA Phone: +33 1 49966312
Baptiste Coudurier <baptiste.coudurier@smartjog.com> writes:
Måns Rullgård wrote:
Michael Niedermayer <michaelni@gmx.at> writes:
Hi
On Mon, Jul 17, 2006 at 01:09:37AM +0100, Måns Rullgård wrote:
michael <subversion@mplayerhq.hu> writes:
Note, this is the same format these codecs use in matroska + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes)
It's actually 00 00 00 01 (four bytes) for the NAL units that we're dealing with here. To make this unambiguous, I would change the text to read
For H.264 the format MUST be that specified in ITU-T Rec. H.264 Annex B Byte stream format. agree, but we should still mention that its 0 0 0 1 + NAL as not every reader of nut.txt will have (or want) every spec of every codec ...
Fine by me. I just want the proper reference included for those that do have the document.
Actually, some NALs (PPS, SPS ?) can start with 00 00 01 IIRC.
Actually, it's the opposite. Quote from the spec: When any of the following conditions are fulfilled, the zero_byte syntax element shall be present. - the nal_unit_type within the nal_unit( ) is equal to 7 (sequence parameter set) or 8 (picture parameter set) - the byte stream NAL unit syntax structure contains the first NAL unit of an access unit in decoding order, as specified by subclause 7.4.1.2.3. -- Måns Rullgård mru@inprovide.com
Hi Måns Rullgård wrote:
[...]
Actually, some NALs (PPS, SPS ?) can start with 00 00 01 IIRC.
Actually, it's the opposite. Quote from the spec:
When any of the following conditions are fulfilled, the zero_byte syntax element shall be present.
- the nal_unit_type within the nal_unit( ) is equal to 7 (sequence parameter set) or 8 (picture parameter set) - the byte stream NAL unit syntax structure contains the first NAL unit of an access unit in decoding order, as specified by subclause 7.4.1.2.3.
Ah thanks. That is indeed simpler than putting the NAL size ;) -- Baptiste COUDURIER GnuPG Key Id: 0x5C1ABAAA SMARTJOG S.A. http://www.smartjog.com Key fingerprint 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA Phone: +33 1 49966312
participants (4)
-
Baptiste Coudurier -
michael -
Michael Niedermayer -
Måns Rullgård