[FFmpeg-devel] [PATCH 1/9] crc: add AV_CRC_8_SBC as a 8 bits CRC with polynomial 0x1D

[Rostislav Pehlivanov]

On 23 December 2017 at 20:38, Aurelien Jacobs <aurel at gnuage.org> wrote:

> On Sat, Dec 23, 2017 at 04:32:26PM -0300, James Almer wrote:
> > On 12/23/2017 3:01 PM, Aurelien Jacobs wrote:
> > > ---
> > >  libavutil/crc.c       | 26 ++++++++++++++++++++++++++
> > >  libavutil/crc.h       |  1 +
> > >  libavutil/tests/crc.c |  7 ++++---
> > >  tests/ref/fate/crc    |  1 +
> > >  4 files changed, 32 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/libavutil/crc.c b/libavutil/crc.c
> > > index d44550c9c0..8e44a76ec8 100644
> > > --- a/libavutil/crc.c
> > > +++ b/libavutil/crc.c
> > > @@ -52,6 +52,30 @@ static const AVCRC av_crc_table[AV_CRC_MAX][257] = {
> > >          0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB, 0xE6, 0xE1,
> 0xE8, 0xEF,
> > >          0xFA, 0xFD, 0xF4, 0xF3, 0x01
> > >      },
> > > +    [AV_CRC_8_SBC] = {
> > > +        0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53, 0xE8, 0xF5,
> 0xD2, 0xCF,
> > > +        0x9C, 0x81, 0xA6, 0xBB, 0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4,
> 0x83, 0x9E,
> > > +        0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76, 0x87, 0x9A,
> 0xBD, 0xA0,
> > > +        0xF3, 0xEE, 0xC9, 0xD4, 0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06,
> 0x21, 0x3C,
> > > +        0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19, 0xA2, 0xBF,
> 0x98, 0x85,
> > > +        0xD6, 0xCB, 0xEC, 0xF1, 0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A,
> 0x5D, 0x40,
> > > +        0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8, 0xDE, 0xC3,
> 0xE4, 0xF9,
> > > +        0xAA, 0xB7, 0x90, 0x8D, 0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F,
> 0x78, 0x65,
> > > +        0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7, 0x7C, 0x61,
> 0x46, 0x5B,
> > > +        0x08, 0x15, 0x32, 0x2F, 0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30,
> 0x17, 0x0A,
> > > +        0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2, 0x26, 0x3B,
> 0x1C, 0x01,
> > > +        0x52, 0x4F, 0x68, 0x75, 0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7,
> 0x80, 0x9D,
> > > +        0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8, 0x03, 0x1E,
> 0x39, 0x24,
> > > +        0x77, 0x6A, 0x4D, 0x50, 0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8,
> 0xEF, 0xF2,
> > > +        0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A, 0x6C, 0x71,
> 0x56, 0x4B,
> > > +        0x18, 0x05, 0x22, 0x3F, 0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED,
> 0xCA, 0xD7,
> > > +        0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66, 0xDD, 0xC0,
> 0xE7, 0xFA,
> > > +        0xA9, 0xB4, 0x93, 0x8E, 0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91,
> 0xB6, 0xAB,
> > > +        0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43, 0xB2, 0xAF,
> 0x88, 0x95,
> > > +        0xC6, 0xDB, 0xFC, 0xE1, 0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33,
> 0x14, 0x09,
> > > +        0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C, 0x97, 0x8A,
> 0xAD, 0xB0,
> > > +        0xE3, 0xFE, 0xD9, 0xC4, 0x01
> > > +    },
> > >      [AV_CRC_16_ANSI] = {
> > >          0x0000, 0x0580, 0x0F80, 0x0A00, 0x1B80, 0x1E00, 0x1400,
> 0x1180,
> > >          0x3380, 0x3600, 0x3C00, 0x3980, 0x2800, 0x2D80, 0x2780,
> 0x2200,
> > > @@ -305,6 +329,7 @@ static void id ## _init_table_once(void)
> > >  #define CRC_INIT_TABLE_ONCE(id) ff_thread_once(&id ## _once_control,
> id ## _init_table_once)
> > >
> > >  DECLARE_CRC_INIT_TABLE_ONCE(AV_CRC_8_ATM,      0,  8,       0x07)
> > > +DECLARE_CRC_INIT_TABLE_ONCE(AV_CRC_8_SBC,      0,  8,       0x1D)
> >
> > The polynomial 0x1D seems to be used in a couple standards, including
> > one defined by the European Broadcasting Union, so instead of _SBC which
> > is a codec using the CRC, I'd use _EBU for the enum constant.
>
> Agreed. Here is an updated patch.
>
>
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>
Patch LGTM, will apply tonight if no one objects.