This is a project that uses the official Blackmagic Raw SDK to decode a
*.braw
file in a way that can be read by FFmpeg. The goal of the
project is to allow unattended, headless, conversion of *.braw
files
into other file formats.
From meisa233: I just make some changes and make it run on macOS which passed the test on macOS 10.14.
I'll start right off by showing you some examples of how the
braw-decode
program may be used.
Generate proxy editing files: (In the root folder of braw-decode)
./braw-decode -s 2 sample.braw | ./ffmpeg -y -i sample.braw $(./braw-decode -s 2 -f sample.braw) \
-map 1:v:0 -map 0:a:0 -c:a copy \
-c:v dnxhd -vf "scale=1280:720,format=yuv422p" -b:v 60M output.mov
Convert to 10b 32Mbps h265 for archiving using NVENC using 16 bit source:
./braw-decode -v -c 16pl sample.braw | ./ffmpeg -y -i sample.braw $(./braw-decode -c 16pl -f sample.braw) \
-map 1:v:0 -map 0:a:0 -c:a copy \
-c:v hevc_nvenc -b:v 32M -profile:v rext output.mov
braw-decode
has two main purposes in the conversion process.
- Decode the
*.braw
file into a format FFMpeg can read - Provide FFmpeg with the parameters to interpret the decoded data
The first stage of braw-decode
will read a *.braw
as pure RGB
data out to the standard CLI output. This is intended to be piped
directly to FFmpeg. Running braw-decode
without piping it to FFmpeg
will have unintended consequences as it will print all command
characters that happen to be in the *.braw
file without escaping
them.
The second stage prints the parameters needed for FFmpeg to read them decoded data. The program controls the following parameters:
-f rawvideo
: Tellsffmpeg
that it will be decoding a raw data stream-pixel_format
: The layout and bit depth of the data stream-s
: The intended resolution of the incoming data stream-r
: The intended frame rate of the incoming data stream-i pipe:0
: Tellsffmpeg
to read the data fromstdin
- Optional
-filter:v colorchannelmixer=0:1:0:0:0:0:1:0:1:0:0:0
: Needed to correct color channels*
*FFmpeg does not have a planar 16 bit format in RGB channel sequence. The colorchannelmixer
is used to correct the colors as a filter stage
You may choose not to use braw-decode
to control the input
parameters but you will need to specify them manually in its place.
braw-decode
does nothing with audio at all as it is not needed.
*.braw
files use the mov
container format and a standard
pcm_s24le
audio stream. This can be read directly by FFmpeg
without conversion by using a *.braw
file as an input and mapping
its audio channel to the output. The examples demonstrate this.
Some options of the Blackmagic Raw SDK that control the decoding of
*.braw
files have been exposed as arguments for braw-decode
. The
following complete listing of the arguments may be printed at any
time by running braw-decode -h
:
braw-decode - BRAW file decoder
Usage: braw-decode sample.braw | ffmpeg -y $(braw-decode -f sample.braw) -c:v hevc_nvenc output.mov
-n, --info
Print details of clip
-v, --verbose
Print more information to CERR while processing
-f, --ff-format
Print FFmpeg arguments for processing decoded video
Example: '-f rawvideo -pixel_format rgba -s 3840x2160 -r 60 -i pipe:0`
-h, --help
Print help text
-c, --color-format [VALUE]
Bit depth and order of color information to be output:
Options:
rgba - Unsigned 8bit interleaved RGBA (FFmpeg format: rgba)
bgra - Unsigned 8bit interleaved BGRA (FFmpeg format: bgra)
16il - Unsigned 16bit interleaved RGB (FFmpeg format: rgb48le)
16pl - Unsigned 16bit planar RGB (FFmpeg format: gbrp16le)
f32s - Floating point interleaved RGB
f32p - Floating point planar RGB
f32a - Floating point interleaved BGRA
-t, --threads [VALUE]
Number of CPU threads to use for decoding
-i, --in [VALUE]
Start frame index for decoding
-o, --out [VALUE]
End frame index for decoding
-s, --scale [VALUE]
Scale input video down by this factor.
WARNING: Only the 8bit color formats at half scale seem to work
Options:
1
2
4
8
Most of these are well enough documented there but some could use additional information:
Verbose mode in braw-decode
must print messages to stderr
as
stdout
is used to send data to FFmpeg. Additionally it will print
real time information about the current frame and active number
of CPU threads on a single line intended to provide more information
alongside the normal FFmpeg encoding status.
All supported methods of decoding *.braw
files supported by the
SDK have been made available, but not all are compatible with
FFmpeg. rawvideo
sources must be explicitly decoded in specific
ways. While FFmpeg has support for 32 bit floats, in my testing
none of the available formats match those used in the SDK. As such
they should be considered non-functional when using braw-decode
with FFmpeg.
Additionally, as mentioned in Usage, the 16 bit planar format that FFmpeg supports is BGR formatted while the SDK outputs in RGB. This can be corrected after encoding or as a filter stage though so it has been marked as compatible. I felt this to be important as the 16 bit planar format is faster than the interleaved format based on my testing.
The scale option is handled by the SDK which is important because
it means less data is sent over stdout
improving performance. But
in my testing the scale feature has issues with all color formats
except the 8 bit ones and only 2 or half scaling works with that. As
such I consider the scaling option really only usable for generating
proxy files due to the lower quality, but this still has real world
use so it has been left in.
The remaining scale factors have been included in the program in the hopes that an updated SDK revision will correct the issues.
The Blackmagic Raw SDK supports CPU, OpenCL, CUDA, and Metal
decoding. As of right now braw-decode
only supports CPU decoding.
The SDK does not come with examples that demonstrate OpenCL or Metal
configurations and I have been told by Blackmagic that the CUDA
sample is not configured correctly.
Once an sample of how to configure the hardware accelerated
decoding methods is available it will be added.
Currently braw-decode
has only been compiled for and tested with
Linux. It should be possible to build versions for Windows and MacOS
as the SDK is available for both platforms. I will be starting
development and testing on a Windows version when time is available.
I cannot produce and test a MacOS version as I do not own a
sufficiently new enough Apple computer to work with.
The Blackmagic Raw SDK is the only dependency needed to compile
braw-decode
. It is available from Blackmagic here: https://www.blackmagicdesign.com/products/blackmagicraw
braw-decode
was developed using Version 2.2 of the SDK and the it
has changed multiple times so the following may need to be updated
for later versions.
Setting up the SDK
- Extract the downloaded Blackmagic_RAW_Linux_..tar.gz |
tar -xzf Blackmagic_RAW_Linux*.tar.gz
- Open the Blackmagic RAW folder and extract the rpm |
cd Blackmagic\ RAW && rpm2cpio *.rpm | cpio -idmv
- Go to usr/lib64/blackmagic/BlackmagicRAWSDK/Linux/ |
cd usr/lib64/blackmagic/BlackmagicRAWSDK/Linux/
- Copy the contents of the Include and Libraries folders to the one for
braw-decode
You are now ready to build braw-decode
. The only step needed is:
make
You should now have a braw-decode
executable to run!
A note though, by default braw-decode
looks for the "Libraries"
folder in the path that it is called from. So if you don't run it
from the folder with "Libraries" in it it will crash. If you want
make the program for from anywhere you need to copy contents of the
Libraries folder somewhere like /usr/lib64/brawsdk/
or
/opt/brawsdk/
and change the path in braw.h
that is assigned to
lib
on line 113 and recompile. With a full path it can find the
files from anywhere.
A command line that I tested:
./braw-decode -v -t 4 22_A053_02050638_C011.braw | ./ffmpeg -y -i 22_A053_02050638_C011.braw $(./braw-decode -v -t 4 -f 22_A053_02050638_C011.braw) -map 1:v:0 -map 0:a:0 -vf setfield=tff -flags +ilme+ildct -c:v prores -c:a pcm_s24le -profile:v 2 -vendor apl0 -pix_fmt yuv422p10le -r 25 -s 1920x1080 -y output.mov