[1/2] ffmpeg: don't use hardcoded lookup tables

Message ID 20190719201958.19700-1-ross.burton@intel.com
State Accepted
Commit 51f13afe669638dbf72f464f243adccb22be3d21
Headers show
Series
  • [1/2] ffmpeg: don't use hardcoded lookup tables
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Commit Message

Ross Burton July 19, 2019, 8:19 p.m.
ffmpeg can generate lookup tables at build time instead of runtime, but this is
no longer a recommended option.  The size impact is significant (12% of the
total libavcodec size, nearly 2MB), the runtime impact of dynamic tables isn't
too costly, and only a few codecs actually use the pre-generated tables (MP3,
notably).

Signed-off-by: Ross Burton <ross.burton@intel.com>

---
 meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb | 1 -
 1 file changed, 1 deletion(-)

-- 
2.20.1

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Comments

Khem Raj July 20, 2019, 12:48 a.m. | #1
On Fri, Jul 19, 2019 at 1:20 PM Ross Burton <ross.burton@intel.com> wrote:
>

> ffmpeg can generate lookup tables at build time instead of runtime, but this is

> no longer a recommended option.  The size impact is significant (12% of the

> total libavcodec size, nearly 2MB), the runtime impact of dynamic tables isn't

> too costly, and only a few codecs actually use the pre-generated tables (MP3,

> notably).


I think it will be good to understand the performance impact with some
low end non-x86 device
as for now, it will be better to turn this into a packageconfig knob
instead of just removing the
option

>

> Signed-off-by: Ross Burton <ross.burton@intel.com>

> ---

>  meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb | 1 -

>  1 file changed, 1 deletion(-)

>

> diff --git a/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb b/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb

> index 147388d9b7c..6d230c33169 100644

> --- a/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb

> +++ b/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb

> @@ -106,7 +106,6 @@ EXTRA_OECONF = " \

>      --extra-cflags="${TARGET_CFLAGS} ${HOST_CC_ARCH}${TOOLCHAIN_OPTIONS}" \

>      --extra-ldflags="${TARGET_LDFLAGS}" \

>      --sysroot="${STAGING_DIR_TARGET}" \

> -    --enable-hardcoded-tables \

>      ${EXTRA_FFCONF} \

>      --libdir=${libdir} \

>      --shlibdir=${libdir} \

> --

> 2.20.1

>

> --

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Patch

diff --git a/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb b/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb
index 147388d9b7c..6d230c33169 100644
--- a/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb
+++ b/meta/recipes-multimedia/ffmpeg/ffmpeg_4.1.3.bb
@@ -106,7 +106,6 @@  EXTRA_OECONF = " \
     --extra-cflags="${TARGET_CFLAGS} ${HOST_CC_ARCH}${TOOLCHAIN_OPTIONS}" \
     --extra-ldflags="${TARGET_LDFLAGS}" \
     --sysroot="${STAGING_DIR_TARGET}" \
-    --enable-hardcoded-tables \
     ${EXTRA_FFCONF} \
     --libdir=${libdir} \
     --shlibdir=${libdir} \