[FFmpeg-devel] MPEG decoding on the iPhone is buggy

[Jason Millard]

> I get an error with libavcodec/arm/dsputil_arm_s.S, which starts with this:
>
> /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin9-gcc-4.0.1
> -DHAVE_AV_CONFIG_H -I.
> -I"/Users/yonilevy/projects/vidvid/tryingFreshWithoutOpt/ffmpeg"
> -D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112 -D_FILE_OFFSET_BITS=64
> -D_LARGEFILE_SOURCE -arch armv6 -pipe -miphoneos-version-min=2.0 -isysroot
> /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS2.1.sdk
>
> -I/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS2.1.sdk/usr/include/gcc/darwin/4.0
>  -mdynamic-no-pic -MMD -MF libavcodec/arm/dsputil_arm_s.d -MT
> libavcodec/arm/dsputil_arm_s.o -c -o libavcodec/arm/dsputil_arm_s.o
> libavcodec/arm/dsputil_arm_s.Slibavcodec/arm/dsputil_arm_s.S:106:Rest of
> line ignored. 1st junk character valued 92 (\).
>
> The rest can be found here: http://pastebin.com/f10a2739b.
> I then tried compiling with --enable-armv6 and got the same error.
> Just to make sure the patches still work, I applied ffmpeg4iphone patches
> and recompiled, it works.
>
>
>
You'll definitely want to compile with the latest iPhone SDK and use GCC
4.2. If you use 4.0.1, ffmpeg libraries run extremely slow.
I run into the same compile issues you are running into with dsputil_arm_s.S
and a few others, so I usually just shut off ARM optimizations off all
together.

./configure --enable-cross-compile --arch=arm --disable-armv5te
--disable-armv6 --disable-armv6t2 --disable-armvfp --disable-iwmmxt
--disable-altivec --disable-neon --cc=arm-apple-darwin9-gcc-4.2.1

After ./configure, I go in and manually edit config.h and config.mak:

ARCH_ARM no
HAVE_ARCH_ARM 0

-- Jason