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

[Vladimir Voroshilov]

2009/6/19 Michael Niedermayer <michaelni at gmx.at>:
> 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

Rewrote in math art.
I left "sum", since upper sigma takes too lot of space.




-- 
Regards,
Vladimir Voroshilov     mailto:voroshil at gmail.com
JID: voroshil at gmail.com, voroshil at jabber.ru
ICQ: 95587719
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