How-to: cross-compile ffmpeg for readynas sparc

Since I really needed ffmpeg I cross-compiled it myself. I didn't do a proper deb, I just used the upstream sources and hacked until it worked. You may follow these instructions to achieve the same:


cross-compile ffmpeg for ReadyNAS NV+ (SPARC) pseudo how-to
v0.01 (2012-01-10)

Because I couldn't find ffmpeg for the ReadyNAS Sparc, I had to figure out how to compile it. I am not an experienced programmer, that's why these instructions are by far not perfect and I do not know a lot better. In addition, I tried several ways and I didn't start over just to test these instructions; therefore there might be some steps missing or not working. If you work through, please add any corrections in comments.

Overview:
- install a sarge chroot
- get the chroot ready
- add the readynas cross-compiler
- get the ffmpeg sources and edit ./configure
- compile
- transfer and install


Details:
Get your hands on a Debian installation. This can be a real or a virtual machine, I think it is mandatory to have a x86 architecture for the ReadyNAS cross-compiler.

1) install a sarge chroot
-------------------------
- Install debootstrap and chroot with:

	apt-get install debootstrap coreutils

- Make a new directory "debian-sarge-cross-chroot":

	mkdir debian-sarge-cross-chroot

- Install Debian in this directory:

	debootstrap --arch i386 sarge debian-sarge-cross-chroot http://archive.debian.org/debian

- Enter the chroot:

	chroot debian-sarge-cross-chroot

2) get the chroot ready
-----------------------
- Edit the package sources:

	nano /etc/apt/sources.list

...and add sarge-backports to list of sources:

	deb-src http://archive.debian.org/debian sarge main contrib non-free

	deb http://archive.debian.org/backports.org sarge-backports main contrib non-free
	deb-src http://archive.debian.org/backports.org sarge-backports main contrib non-free

(Do not delete the existing line, just add the above lines.)
...save and exit nano (CTRL-X).

- Install some packages:

	apt-get update
	apt-get install build-essential less locales wget
	apt-get -t sarge-backports install make texi2html

- Add "LC_ALL=en_US.UTF-8" to /etc/environment if nothing for LC_ALL is there.

- Exit and reenter the chroot:

	exit
	chroot debian-sarge-cross-chroot

3) add the readynas cross-compiler to your chroot
-------------------------------------------------
- Get the ReadyNAS cross-compiler:

	cd /root
	wget http://www.readynas.com/download/development/readynas-cross-3.3.5.tar.gz

- Upack:

	cd /
	tar -xvvzf root/readynas-cross-3.3.5.tar.gz

- Since I do not know how to tell ffmpeg to use the right compiler, I cheated like this:

	cd /usr/bin
	mkdir x86
	for prg in `which $(ls -1 /usr/bin/sparc-linux-* | sed -e "s%^/usr/bin/sparc-linux-%%g")`; do mv -v "$prg" x86/. ; done
	for prg in $(ls -1 sparc-linux-* | sed -e "s%^sparc-linux-%%g"); do ln -vs "sparc-linux-$prg" "$prg" ; done

... this moves the original compiler files away and links the sparc-cross-compiler ones in place. Check the result:

	ls -la | grep sparc

resp.

	gcc --version

...should reveal "gcc (GCC) 3.3.5 (Infrant 3.3.5-1)"
(You may undo this with: cd /usr/bin ; for prg in $(ls -1 sparc-linux-* | sed -e "s%^sparc-linux-%%g"); do rm -v "$prg" ; done)


4) get the ffmpeg sources and edit ./configure
----------------------------------------------
- You can't use wget to get the sources. Point your browser to
http://git.videolan.org/?p=ffmpeg.git;a=snapshot;h=HEAD;sf=tgz
and download the file. Transfer it inside your chroot folder
debian-sarge-cross-chroot/usr/src

- Get back into your terminal and change to that location:

	cd /usr/src

- Unpack:

	tar -xvvzf ffmpeg-HEAD-dd3ca3ea.tar.gz 

(Your download might be newer and thus named differently.)

- Enter the newly created directory:

	cd ffmpeg-HEAD-dd3ca3ea

- Unfortunately the configure script compiles for ultrasparc instead of v8 if given the architecture sparc.
I hacked the configure script to not do this. It is not the correct way I did it, but it works.
Create the patch file:

	nano configure.diff

Add the following lines:

--- configure.orig      2012-01-10 02:50:41.000000000 +0000
+++ configure   2012-01-10 13:41:38.519916764 +0000
@@ -2448,6 +2448,12 @@
         sparc64)
             cpuflags="-mcpu=v9"
         ;;
+       v7)
+          cpuflags="-mcpu=v7"
+       ;;
+       v8)
+          cpuflags="-mcpu=v8"
+       ;;
     esac

 elif enabled arm; then
@@ -2891,7 +2897,7 @@
 elif enabled sparc; then

     enabled vis && check_asm vis '"pdist %f0, %f0, %f0"' -mcpu=ultrasparc &&
-        add_cflags -mcpu=ultrasparc -mtune=ultrasparc
+        add_cflags -mcpu=v8 -mtune=v8

 elif enabled x86; then

- Save and exit nano (CTRL-X).

- Apply the patch:

	patch -p0 configure configure.diff

5) compile
----------
- Run the configure script:

	./configure --logfile=./build.log --prefix=/usr/local/lib/ffmpeg --arch=sparc --cpu=v8 --disable-vis  --target-os=linux --enable-cross-compile

- Run make:

	make

...wait and then run:

	make install

You will find your newly compiled ffmpeg in /usr/local/lib/ffmpeg.

- Build an archive of your compilation:

	tar -cvvzf /usr/src/ffmpeg-HEAD-dd3ca3ea-sparcv8.tar.gz /usr/local/lib/ffmpeg
	cd ..

6) transfer and install
-----------------------
- Tarnsfer your archive file to your ReadyNAS:

	scp ffmpeg-HEAD-dd3ca3ea-sparcv8.tar.gz myreadynas:/root

- SSH into your ReadyNAS and install:

	cd /
	tar -xvvzf root/ffmpeg-HEAD-dd3ca3ea-sparcv8.tar.gz

- Put a link in /usr/local/bin for all executables:

	cd /usr/local/bin
	ln -s ../lib/ffmpeg/bin/*

That's it. *sigh*

Good luck, Adrian Zaugg.


You can download these instructions from http://ente.limmat.ch/ftp/pub/readynas/ffmpeg/README
where you also find the tar archive.

v0.01 (2012-01-10)