[RFC PATCH v2 13/13] apps: cam: Write raw file if PPM cannot be written

[Laurent Pinchart]

Hi Milan,

Thank you for the patch.

On Fri, Jan 24, 2025 at 10:58:04PM +0100, Milan Zamazal wrote:
> `cam' application can be requested to write its output as a PPM file.
> However, this is supported only for certain formats (only BGR888
> currently).  If the output format cannot be written, `cam' reports an
> error and doesn't write anything.
> 
> This is all right with a single stream input but impractical with
> multiple streams of different output formats (e.g. a processed stream +
> a raw stream) where some of them can be written in the supported format
> while the other not.  In such a case, it's better to write the supported
> formats as PPM files and the unsupported formats as raw files, with the
> corresponding warning on stderr.  `.raw' extension is added to the file
> name in such a case to make clear it's not a PPM file.
> 
> This is a sort of hack but serves the purpose for the moment.

Should we instead change the -F option (and the -D and -S options too I
suppose) to act at the stream level instead of the camera level ?

> Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
> ---
>  src/apps/cam/file_sink.cpp | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/src/apps/cam/file_sink.cpp b/src/apps/cam/file_sink.cpp
> index 76e21db9..1a866137 100644
> --- a/src/apps/cam/file_sink.cpp
> +++ b/src/apps/cam/file_sink.cpp
> @@ -7,6 +7,7 @@
>  
>  #include <array>
>  #include <assert.h>
> +#include <errno.h>
>  #include <fcntl.h>
>  #include <iomanip>
>  #include <iostream>
> @@ -133,11 +134,16 @@ void FileSink::writeBuffer(const Stream *stream, FrameBuffer *buffer,
>  	if (fileType_ == FileType::Ppm) {
>  		ret = PPMWriter::write(filename.c_str(), stream->configuration(),
>  				       image->data(0));
> -		if (ret < 0)
> -			std::cerr << "failed to write PPM file `" << filename
> -				  << "'" << std::endl;
> -
> -		return;
> +		if (ret == -EINVAL) {
> +			filename += ".raw";
> +			std::cerr << "cannot write file in PPM format, writing `"
> +				  << filename << "' instead" << std::endl;
> +		} else {
> +			if (ret < 0)
> +				std::cerr << "failed to write PPM file `" << filename
> +					  << "'" << std::endl;
> +			return;
> +		}
>  	}
>  
>  	fd = open(filename.c_str(), O_CREAT | O_WRONLY |

-- 
Regards,

Laurent Pinchart