[FFmpeg-devel] [PATCH] G.729 LSF decoding

[Michael Niedermayer]

On Fri, Jun 19, 2009 at 01:58:29AM +0700, Vladimir Voroshilov wrote:
> 2009/6/19 Michael Niedermayer <michaelni at gmx.at>:
> > On Thu, Jun 18, 2009 at 11:18:53PM +0700, Vladimir Voroshilov wrote:
> >> 2009/6/18 Michael Niedermayer <michaelni at gmx.at>:
> >> > On Thu, Jun 18, 2009 at 08:26:56AM +0700, Vladimir Voroshilov wrote:
> >> >> 2009/6/18 Michael Niedermayer <michaelni at gmx.at>:
> >> >> > On Thu, Jun 18, 2009 at 02:10:52AM +0700, Vladimir Voroshilov wrote:
> >> >> >> 2009/6/18 Diego Biurrun <diego at biurrun.de>:
> >> >> >> > On Thu, Jun 18, 2009 at 02:00:37AM +0700, Vladimir Voroshilov wrote:
> >> >> >> >> First patch for main decoding routine.
> >> >> >> >> Decodes LSF (Linear Spectrum Frequencies, if i'm not wrong).
> >> >> >> >>
> >> >> >> >> --- ffmpeg-r19188/libavcodec/g729dec.c
> >> >> >> >> +++ ffmpeg-r19188_v153/libavcodec/g729dec.c
> >> >> >> >> @@ -114,8 +119,74 @@ static inline int get_parity(uint8_t value)
> >> >> >> >>
> >> >> >> >> + ? ?/* Rotate past_quantizer_outputs. */
> >> >> >> >> + ? ?for(k=MA_NP-1; k>0; k--)
> >> >> >> >
> >> >> >> > nit: inconsistently formatted for construct
> >> >> >>
> >> >> >> Damn. One was overlooked...
> >> >> >> Fixed.
> >> >> >>
> >> >> >
> >> >> > [...]
> >> >> >> @@ -114,8 +119,74 @@ static inline int get_parity(uint8_t value)
> >> >> >> ? ? return (0x6996966996696996ULL >> (value >> 2)) & 1;
> >> >> >> ?}
> >> >> >>
> >> >> >> +/**
> >> >> >> + * Saves quantized LSF coefficients for use in next frame.
> >> >> >> + * @param past_quantizer_outputs [in/out] (2.13) quantizer outputs from previous frames
> >> >> >> + * @param quantizer_output (2.13) current quantizer output
> >> >> >> + */
> >> >> >> +static void lq_rotate(int16_t past_quantizer_outputs[MA_NP][10],
> >> >> >> + ? ? ? ? ? ? ? ? ? ? ?const int16_t* quantizer_output)
> >> >> >> +{
> >> >> >> + ? ?int k;
> >> >> >> +
> >> >> >> + ? ?/* Rotate past_quantizer_outputs. */
> >> >> >> + ? ?for (k = MA_NP - 1; k > 0; k--)
> >> >> >> + ? ? ? ?memcpy(past_quantizer_outputs[k], past_quantizer_outputs[k-1], 10 * sizeof(int16_t));
> >> >> >> + ? ?memcpy(past_quantizer_outputs[0], quantizer_output, 10 * sizeof(int16_t));
> >> >> >> +}
> >> >> >
> >> >> > used just once and 3 lines, must be inlined
> >> >> >
> >> >> > note: memcpy() will not be approved before the neccessarity is clear
> >> >>
> >> >> Replaced several memcpy with pointer rotation via memmove.
> >> >> Is such fix enough (patch attached)?
> >> >
> >> > its better, still the 2 line function that is used once remains and
> >> > as said it should be inlined
> >>
> >> I misunderstood you about inlining. Now fixed.
> >>
> >> >
> >> > [...]
> >> >> @@ -124,6 +192,23 @@ static av_cold int decoder_init(AVCodecContext * avctx)
> >> >> ? ? ?/* Both 8kbit/s and 6.4kbit/s modes uses two subframes per frame. */
> >> >> ? ? ?avctx->frame_size = SUBFRAME_SIZE << 1;
> >> >>
> >> >> + ? ?for (k = 0; k < MA_NP + 1; k++) {
> >> >
> >> >> + ? ? ? ?ctx->past_quantizer_outputs[k] = av_malloc(10 * sizeof(int16_t));
> >> >
> >> > this is unacceptable
> >> > put the array in the struct, not allocate 20byte pieces with malloc
> >>
> >> Is attached acceptable?
> >> Or can it be improved ?somehow?
> >>
> >>
> >> >
> >> > [...]
> >> > --
> >> > Michael ? ? GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >> >
> >> > In fact, the RIAA has been known to suggest that students drop out
> >> > of college or go to community college in order to be able to afford
> >> > settlements. -- The RIAA
> >> >
> >> > -----BEGIN PGP SIGNATURE-----
> >> > Version: GnuPG v1.4.9 (GNU/Linux)
> >> >
> >> > iD8DBQFKOhupYR7HhwQLD6sRAirVAJ416btGbzTZMdk+piKNO8Li7QR2iwCgidy9
> >> > 8I0/9076Por+onuUpqMksWA=
> >> > =90Gn
> >> > -----END PGP SIGNATURE-----
> >> >
> >> > _______________________________________________
> >> > ffmpeg-devel mailing list
> >> > ffmpeg-devel at mplayerhq.hu
> >> > https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel
> >> >
> >>
> >>
> >>
> >> --
> >> Regards,
> >> Vladimir Voroshilov ? ? mailto:voroshil at gmail.com
> >> JID: voroshil at gmail.com, voroshil at jabber.ru
> >> ICQ: 95587719
> >
> >> ?g729data.h | ? ?9 +++++++
> >> ?g729dec.c ?| ? 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >> ?2 files changed, 79 insertions(+)
> >> 92e00ddb456d759a865f027baa9472f52189ff32 ?0002-LSF-decoding-routines.159.patch
> >> From 68af3a99f7f09671070c8f1cfe2414dead6f1216 Mon Sep 17 00:00:00 2001
> >> From: Vladimir Voroshilov <voroshil at gmail.com>
> >> Date: Sat, 6 Jun 2009 08:00:56 +0700
> >> Subject: [PATCH] LSF decoding routines
> >>
> >>
> >
> >> diff --git ffmpeg-r19215/libavcodec/g729data.h ffmpeg-r19215_v159/libavcodec/g729data.h
> >> index 796d24e..ce6ab3d 100644
> >> --- ffmpeg-r19215/libavcodec/g729data.h
> >> +++ ffmpeg-r19215_v159/libavcodec/g729data.h
> >> @@ -262,4 +262,13 @@ static const int16_t cb_ma_predictor[2][MA_NP][10] = { /* (0.15) */
> >> ? ? ?{ 3024, ?1592, ? 940, ?1631, ?1723, ?1579, ?2034, ?2084, ?1913, ?2601}
> >> ? ?}
> >> ?};
> >> +
> >> +/**
> >> + * ff_g729_cb_ma_predictor_sum[i] := 1-sum{1}{4}{ff_g729_cb_ma_predictor[k][i]}
> >
> > what is := supposed to mean? its not math and not C, so it seems not ideal
> > in a C file ...
> 
> 
> Entire equation is equall to:
> 
> for (i=0; i<10; i++ {
>  ff_g729_cb_ma_predictor_sum[i] = 1;
>  for (k=0; k<3; k++)
>    ff_g729_cb_ma_predictor_sum[i] -= ff_g729_cb_ma_predictor[k][i]
> }
> 
> Should i replace that short equation with this C code ?

no, i suggest ascii art with the proper math symbols

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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