From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Cc: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Subject: [FFmpeg-devel] [PATCH 12/13] avcodec/dca_lbr: Hardcode lpc table to save space
Date: Tue, 13 Sep 2022 13:33:09 +0200
Message-ID: <GV1P250MB0737FE432B494D184BD6F7DD8F479@GV1P250MB0737.EURP250.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <GV1P250MB0737F59A25C260BC89CFE14F8F479@GV1P250MB0737.EURP250.PROD.OUTLOOK.COM>
The code to initialize it takes more space (in .text) than
the table to be initialized (namely 86B vs 64B for GCC 11.2
with -O3 in an av_cold function), so hardcode the table.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
libavcodec/dca_lbr.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/libavcodec/dca_lbr.c b/libavcodec/dca_lbr.c
index 579bd9c469..9a0eb62f06 100644
--- a/libavcodec/dca_lbr.c
+++ b/libavcodec/dca_lbr.c
@@ -119,7 +119,17 @@ static const uint16_t channel_layouts[7] = {
};
static float cos_tab[256];
-static float lpc_tab[16];
+static const float lpc_tab[16] = {
+ /* lpc_tab[i] = sin((i - 8) * (M_PI / ((i < 8) ? 17 : 15))) */
+ -0.995734176295034521871191178905, -0.961825643172819070408796290732,
+ -0.895163291355062322067016499754, -0.798017227280239503332805112796,
+ -0.673695643646557211712691912426, -0.526432162877355800244607799141,
+ -0.361241666187152948744714596184, -0.183749517816570331574408839621,
+ 0.0, 0.207911690817759337101742284405,
+ 0.406736643075800207753985990341, 0.587785252292473129168705954639,
+ 0.743144825477394235014697048974, 0.866025403784438646763723170753,
+ 0.951056516295153572116439333379, 0.994521895368273336922691944981
+};
av_cold void ff_dca_lbr_init_tables(void)
{
@@ -127,9 +137,6 @@ av_cold void ff_dca_lbr_init_tables(void)
for (i = 0; i < 256; i++)
cos_tab[i] = cos(M_PI * i / 128);
-
- for (i = 0; i < 16; i++)
- lpc_tab[i] = sin((i - 8) * (M_PI / ((i < 8) ? 17 : 15)));
}
static int parse_lfe_24(DCALbrDecoder *s)
--
2.34.1
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next prev parent reply other threads:[~2022-09-13 11:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-13 11:28 [FFmpeg-devel] [PATCH 01/13] avcodec/dolby_e_parser: Remove unnecessary headers Andreas Rheinhardt
2022-09-13 11:32 ` [FFmpeg-devel] [PATCH 02/13] avcodec/dcahuff: Remove unused define Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 03/13] avcodec/dcahuff: Avoid redundant offset table Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 04/13] avcodec/dca_core, dcahuff: Don't use DCAVLC unnecessarily Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 05/13] avcodec/dcahuff: Always use three bits for transition mode VLCs Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 06/13] avcodec/dcaenc: Create encoder-adapted tables Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 07/13] avcodec/dcahuff: Combine tables, use ff_init_vlc_from_lengths() Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 08/13] avcodec/dcahuff, dca_core, dca_lbr: Apply offset during VLC creation Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 09/13] avcodec/dca_core: Inline number of bits of scale factor VLCs Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 10/13] avcodec/dca_core: Don't use too big max_depth in get_vlc2() Andreas Rheinhardt
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 11/13] avcodec/dcahuff: Replace DCAVLC by ordinary VLCs Andreas Rheinhardt
2022-09-13 11:33 ` Andreas Rheinhardt [this message]
2022-09-13 11:33 ` [FFmpeg-devel] [PATCH 13/13] avcodec/dca_lbr: Inline nb_bits for VLCs Andreas Rheinhardt
2022-09-15 19:34 ` [FFmpeg-devel] [PATCH 01/13] avcodec/dolby_e_parser: Remove unnecessary headers Andreas Rheinhardt
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