[AVTCORE] [Technical Errata Reported] RFC2435 (4095)

[RFC Errata System <[e-mail]>]

The following errata report has been submitted for RFC2435,
"RTP Payload Format for JPEG-compressed Video".

--------------------------------------
You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=2435&eid=4095

--------------------------------------
Type: Technical
Reported by: Julius Richard Friedman <[e-mail]>

Section: Appendix B

Original Text
-------------
int MakeHeaders(u_char *p, int type, int w, int h, u_char *lqt,
                u_char *cqt, u_short dri)
{
        u_char *start = p;

        /* convert from blocks to pixels */
        w <<= 3;
        h <<= 3;



Berc, et. al.               Standards Track                    [Page 19]
 
RFC 2435              RTP Payload Format for JPEG           October 1998


        *p++ = 0xff;
        *p++ = 0xd8;            /* SOI */

        p = MakeQuantHeader(p, lqt, 0);
        p = MakeQuantHeader(p, cqt, 1);

        if (dri != 0)
                p = MakeDRIHeader(p, dri);

        *p++ = 0xff;
        *p++ = 0xc0;            /* SOF */
        *p++ = 0;               /* length msb */
        *p++ = 17;              /* length lsb */
        *p++ = 8;               /* 8-bit precision */
        *p++ = h >> 8;          /* height msb */
        *p++ = h;               /* height lsb */
        *p++ = w >> 8;          /* width msb */
        *p++ = w;               /* wudth lsb */
        *p++ = 3;               /* number of components */
        *p++ = 0;               /* comp 0 */
        if (type == 0)
                *p++ = 0x21;    /* hsamp = 2, vsamp = 1 */
        else
                *p++ = 0x22;    /* hsamp = 2, vsamp = 2 */
        *p++ = 0;               /* quant table 0 */
        *p++ = 1;               /* comp 1 */
        *p++ = 0x11;            /* hsamp = 1, vsamp = 1 */
        *p++ = 1;               /* quant table 1 */
        *p++ = 2;               /* comp 2 */
        *p++ = 0x11;            /* hsamp = 1, vsamp = 1 */
        *p++ = 1;               /* quant table 1 */
        p = MakeHuffmanHeader(p, lum_dc_codelens,
                              sizeof(lum_dc_codelens),
                              lum_dc_symbols,
                              sizeof(lum_dc_symbols), 0, 0);
        p = MakeHuffmanHeader(p, lum_ac_codelens,
                              sizeof(lum_ac_codelens),
                              lum_ac_symbols,
                              sizeof(lum_ac_symbols), 0, 1);
        p = MakeHuffmanHeader(p, chm_dc_codelens,
                              sizeof(chm_dc_codelens),
                              chm_dc_symbols,
                              sizeof(chm_dc_symbols), 1, 0);
        p = MakeHuffmanHeader(p, chm_ac_codelens,
                              sizeof(chm_ac_codelens),
                              chm_ac_symbols,
                              sizeof(chm_ac_symbols), 1, 1);




Berc, et. al.               Standards Track                    [Page 20]
 
RFC 2435              RTP Payload Format for JPEG           October 1998


        *p++ = 0xff;
        *p++ = 0xda;            /* SOS */
        *p++ = 0;               /* length msb */
        *p++ = 12;              /* length lsb */
        *p++ = 3;               /* 3 components */
        *p++ = 0;               /* comp 0 */
        *p++ = 0;               /* huffman table 0 */
        *p++ = 1;               /* comp 1 */
        *p++ = 0x11;            /* huffman table 1 */
        *p++ = 2;               /* comp 2 */
        *p++ = 0x11;            /* huffman table 1 */
        *p++ = 0;               /* first DCT coeff */
        *p++ = 63;              /* last DCT coeff */
        *p++ = 0;               /* sucessive approx. */

        return (p - start);
};


Corrected Text
--------------
int MakeHeaders(u_char *p, int type, int w, int h, u_char *lqt,
                u_char *cqt, u_short dri)
{
        u_char *start = p;

        /* convert from blocks to pixels */
        w <<= 3;
        h <<= 3;
        *p++ = 0xff;
        *p++ = 0xd8;            /* SOI */

        p = MakeQuantHeader(p, lqt, 0);
        if(cqt != NULL) p = MakeQuantHeader(p, cqt, 1);

        if (dri != 0)
                p = MakeDRIHeader(p, dri);

        *p++ = 0xff;
        *p++ = 0xc0;            /* SOF */
        *p++ = 0;               /* length msb */
        *p++ = 17;              /* length lsb */
        *p++ = 8;               /* 8-bit precision */
        *p++ = h >> 8;          /* height msb */
        *p++ = h;               /* height lsb */
        *p++ = w >> 8;          /* width msb */
        *p++ = w;               /* wudth lsb */
        *p++ = 3;               /* number of components */
        *p++ = 1;               /* comp 1 */
        if (type == 0)
                *p++ = 0x21;    /* hsamp = 2, vsamp = 1 */
        else
                *p++ = 0x22;    /* hsamp = 2, vsamp = 2 */
        *p++ = 0;               /* quant table 0 */
        *p++ = 1;               /* comp 1 */
        *p++ = 0x11;            /* hsamp = 1, vsamp = 1 */
        *p++ = 1;               /* quant table 1 */
        *p++ = 2;               /* comp 2 */
        *p++ = 0x11;            /* hsamp = 1, vsamp = 1 */
        *p++ = 1;               /* quant table 1 */
        p = MakeHuffmanHeader(p, lum_dc_codelens,
                              sizeof(lum_dc_codelens),
                              lum_dc_symbols,
                              sizeof(lum_dc_symbols), 0, 0);
        p = MakeHuffmanHeader(p, lum_ac_codelens,
                              sizeof(lum_ac_codelens),
                              lum_ac_symbols,
                              sizeof(lum_ac_symbols), 0, 1);
        if(cqt != NULL)
        {
        p = MakeHuffmanHeader(p, chm_dc_codelens,
                              sizeof(chm_dc_codelens),
                              chm_dc_symbols,
                              sizeof(chm_dc_symbols), 1, 0);
        p = MakeHuffmanHeader(p, chm_ac_codelens,
                              sizeof(chm_ac_codelens),
                              chm_ac_symbols,
                              sizeof(chm_ac_symbols), 1, 1);
       }




Berc, et. al.               Standards Track                    [Page 20]
 
RFC 2435              RTP Payload Format for JPEG           October 1998


        *p++ = 0xff;
        *p++ = 0xda;            /* SOS */
        *p++ = 0;               /* length msb */
        *p++ = cqt != NULL ? 0x12 : 0x0b;/* length lsb */
        *p++ = cqt != NULL ? 0x03 : 0x01;/* 3 components */
        *p++ = 0;               /* comp 0 */
        *p++ = 0;               /* huffman table 0 */
        *p++ = 0x01;               /* comp 1 */
        *p++ = cqt != NULL ? 0x11 : 0x00;/* huffman table 1 */
        if(cqt != NULL) *p++ = 2;/* comp 2 */
        *p++ = cqt != NULL ? 0x11 : 0x00;/* huffman table 1 */
        *p++ = 0;               /* first DCT coeff */
        *p++ = 63;              /* last DCT coeff */
        *p++ = 0;               /* sucessive approx. */

        return (p - start);
};


Notes
-----
Did not take into account cases with only 1 component was used.

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-------------
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--------------------------------------
RFC2435 (no draft string recorded)
--------------------------------------
Title               : RTP Payload Format for JPEG-compressed Video
Publication Date    : October 1998
Author(s)           : L. Berc, W. Fenner, R. Frederick, S. McCanne, P. Stewart
Category            : PROPOSED STANDARD
Source              : Audio/Video Transport
Area                : Real-time Applications and Infrastructure
Stream              : IETF
Verifying Party     : IESG