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media: Add parsing for APP14 data segment in jpeg helpers
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> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
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2 changed files with 61 additions and 1 deletions
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@ -45,6 +45,7 @@ MODULE_LICENSE("GPL");
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#define DHP 0xffde /* hierarchical progression */
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#define EXP 0xffdf /* expand reference */
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#define APP0 0xffe0 /* application data */
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#define APP14 0xffee /* application data for colour encoding */
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#define APP15 0xffef
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#define JPG0 0xfff0 /* extensions */
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#define JPG13 0xfffd
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@ -444,6 +445,39 @@ static int jpeg_skip_segment(struct jpeg_stream *stream)
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return jpeg_skip(stream, len - 2);
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}
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/* Rec. ITU-T T.872 (06/2012) 6.5.3 */
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static int jpeg_parse_app14_data(struct jpeg_stream *stream,
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enum v4l2_jpeg_app14_tf *tf)
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{
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int ret;
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int lp;
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int skip;
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lp = jpeg_get_word_be(stream);
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if (lp < 0)
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return lp;
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/* Check for "Adobe\0" in Ap1..6 */
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if (stream->curr + 6 > stream->end ||
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strncmp(stream->curr, "Adobe\0", 6))
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return -EINVAL;
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/* get to Ap12 */
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ret = jpeg_skip(stream, 11);
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if (ret < 0)
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return ret;
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ret = jpeg_get_byte(stream);
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if (ret < 0)
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return ret;
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*tf = ret;
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/* skip the rest of the segment, this ensures at least it is complete */
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skip = lp - 2 - 11;
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return jpeg_skip(stream, skip);
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}
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/**
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* v4l2_jpeg_parse_header - locate marker segments and optionally parse headers
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* @buf: address of the JPEG buffer, should start with a SOI marker
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@ -476,6 +510,9 @@ int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out)
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if (marker != SOI)
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return -EINVAL;
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/* init value to signal if this marker is not present */
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out->app14_tf = V4L2_JPEG_APP14_TF_UNKNOWN;
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/* loop through marker segments */
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while ((marker = jpeg_next_marker(&stream)) >= 0) {
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switch (marker) {
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@ -519,7 +556,10 @@ int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out)
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ret = jpeg_parse_restart_interval(&stream,
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&out->restart_interval);
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break;
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case APP14:
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ret = jpeg_parse_app14_data(&stream,
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&out->app14_tf);
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break;
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case SOS:
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ret = jpeg_reference_segment(&stream, &out->sos);
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if (ret < 0)
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@ -87,6 +87,24 @@ struct v4l2_jpeg_scan_header {
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/* Ss, Se, Ah, and Al are not used by any driver */
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};
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/**
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* enum v4l2_jpeg_app14_tf - APP14 transform flag
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* According to Rec. ITU-T T.872 (06/2012) 6.5.3
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* APP14 segment is for color encoding, it contains a transform flag,
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* which may have values of 0, 1 and 2 and are interpreted as follows:
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* @V4L2_JPEG_APP14_TF_CMYK_RGB: CMYK for images encoded with four components
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* RGB for images encoded with three components
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* @V4L2_JPEG_APP14_TF_YCBCR: an image encoded with three components using YCbCr
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* @V4L2_JPEG_APP14_TF_YCCK: an image encoded with four components using YCCK
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* @V4L2_JPEG_APP14_TF_UNKNOWN: indicate app14 is not present
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*/
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enum v4l2_jpeg_app14_tf {
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V4L2_JPEG_APP14_TF_CMYK_RGB = 0,
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V4L2_JPEG_APP14_TF_YCBCR = 1,
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V4L2_JPEG_APP14_TF_YCCK = 2,
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V4L2_JPEG_APP14_TF_UNKNOWN = -1,
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};
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/**
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* struct v4l2_jpeg_header - parsed JPEG header
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* @sof: pointer to frame header and size
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@ -102,6 +120,7 @@ struct v4l2_jpeg_scan_header {
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* order, optional
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* @restart_interval: number of MCU per restart interval, Ri
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* @ecs_offset: buffer offset in bytes to the entropy coded segment
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* @app14_tf: transform flag from app14 data
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*
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* When this structure is passed to v4l2_jpeg_parse_header, the optional scan,
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* quantization_tables, and huffman_tables pointers must be initialized to NULL
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@ -121,6 +140,7 @@ struct v4l2_jpeg_header {
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struct v4l2_jpeg_reference *huffman_tables;
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u16 restart_interval;
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size_t ecs_offset;
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enum v4l2_jpeg_app14_tf app14_tf;
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};
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int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out);
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