| Message ID | 20210111192822.12178-1-mirela.rabulea@oss.nxp.com |
|---|---|
| Headers | show |
| Series | Add V4L2 driver for i.MX8 JPEG Encoder/Decoder | expand |
On Mon, 2021-01-11 at 21:28 +0200, Mirela Rabulea wrote: > From: Mirela Rabulea <mirela.rabulea@nxp.com> > > According to Rec. ITU-T T.872 (06/2012) 6.5.3 > APP14 segment is for color encoding, it contains a transform flag, which > may have values of 0, 1 and 2 and are interpreted as follows: > 0 - CMYK for images that are encoded with four components > - RGB for images that are encoded with three components > 1 - An image encoded with three components using YCbCr colour encoding. > 2 - An image encoded with four components using YCCK colour encoding. > > This is used in imx-jpeg decoder, to distinguish between > YUV444 and RGB24. > > Signed-off-by: Mirela Rabulea <mirela.rabulea@nxp.com> > --- > Changes in v7: > Check there are 6 bytes available in the stream before checking for "Adobe\0" > Change jpeg_parse_app14_data function to differentiate between the 3 scenarios: app14 missing, or app14 present but with/without parsing errors: > App14 missing => Added V4L2_JPEG_APP14_TF_UNKNOWN to the enum v4l2_jpeg_app14_tf, use it to indicate app14 & TF is missing > App14 present without parsing errors => Return the transform flag value as enum v4l2_jpeg_app14_tf (new paramater of jpeg_parse_app14_data function) > App14 present with parsing errors => Return -EINVAL from jpeg_parse_app14_data, also return from calling function (v4l2_jpeg_parse_header) when this error is met. > > drivers/media/v4l2-core/v4l2-jpeg.c | 47 +++++++++++++++++++++++++++-- > include/media/v4l2-jpeg.h | 20 ++++++++++++ > 2 files changed, 65 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-jpeg.c b/drivers/media/v4l2-core/v4l2-jpeg.c > index 8947fd95c6f1..8d5fedb136dd 100644 > --- a/drivers/media/v4l2-core/v4l2-jpeg.c > +++ b/drivers/media/v4l2-core/v4l2-jpeg.c > @@ -45,6 +45,7 @@ MODULE_LICENSE("GPL"); > #define DHP 0xffde /* hierarchical progression */ > #define EXP 0xffdf /* expand reference */ > #define APP0 0xffe0 /* application data */ > +#define APP14 0xffee /* application data for colour encoding */ > #define APP15 0xffef > #define JPG0 0xfff0 /* extensions */ > #define JPG13 0xfffd > @@ -444,8 +445,44 @@ static int jpeg_skip_segment(struct jpeg_stream *stream) > return jpeg_skip(stream, len - 2); > } > > +/* Rec. ITU-T T.872 (06/2012) 6.5.3 */ > +static int jpeg_parse_app14_data(struct jpeg_stream *stream, > + enum v4l2_jpeg_app14_tf *tf) > +{ > + int ret; > + int lp; > + int skip; > + > + lp = jpeg_get_word_be(stream); > + if (lp < 0) > + return lp; > + > + /* Check for "Adobe\0" in Ap1..6 */ > + if (stream->curr + 6 > stream->end || > + strncmp(stream->curr, "Adobe\0", 6)) > + return -EINVAL; > + > + /* get to Ap12 */ > + ret = jpeg_skip(stream, 11); > + if (ret < 0) > + return ret; > + > + ret = jpeg_get_byte(stream); > + if (ret < 0) > + return ret; > + > + *tf = ret; > + > + skip = lp - 2 - 11; > + ret = jpeg_skip(stream, skip); > + if (ret < 0) > + return ret; > + > + return 0; This could be simplified to return jpeg_skip(stream, skip); although it would be better style to move the *tf = ... assignment down past the last error return instead. Either way, Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> regards Philipp