[PATCH v2] media: coda: jpeg: support optimized huffman tables

[PATCH v2] media: coda: jpeg: support optimized huffman tables

[Adrian Ratiu]

Each jpeg can have the huffman tables optimized for its specific content
meaning that the table lenghts and values don't match the standard table
of substitutions so there's no reason to hardcode and expect the standard
lengths, otherwise we just end up rejecting optimized jpegs altogether.

Tested on CODA960.

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
Changes since v1:
  - Added test for DC tables upper boundary (Philipp)
---
 drivers/media/platform/coda/coda-jpeg.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/media/platform/coda/coda-jpeg.c b/drivers/media/platform/coda/coda-jpeg.c
index 6a11b64efb6b..60d6e1073334 100644
--- a/drivers/media/platform/coda/coda-jpeg.c
+++ b/drivers/media/platform/coda/coda-jpeg.c
@@ -343,7 +343,10 @@ int coda_jpeg_decode_header(struct coda_ctx *ctx, struct vb2_buffer *vb)
 			v4l2_err(&dev->v4l2_dev, "missing Huffman table\n");
 			return -EINVAL;
 		}
-		if (huffman_tables[i].length != ((i & 2) ? 178 : 28)) {
+		/* AC tables should be between 17 -> 178, DC between 17 -> 28 */
+		if (huffman_tables[i].length < 17 ||
+		    huffman_tables[i].length > 178 ||
+		    ((i & 2) == 0 && huffman_tables[i].length > 28)) {
 			v4l2_err(&dev->v4l2_dev,
 				 "invalid Huffman table %d length: %zu\n",
 				 i, huffman_tables[i].length);
@@ -357,10 +360,12 @@ int coda_jpeg_decode_header(struct coda_ctx *ctx, struct vb2_buffer *vb)
 			return -ENOMEM;
 		ctx->params.jpeg_huff_tab = huff_tab;
 	}
-	memcpy(huff_tab->luma_dc, huffman_tables[0].start, 16 + 12);
-	memcpy(huff_tab->chroma_dc, huffman_tables[1].start, 16 + 12);
-	memcpy(huff_tab->luma_ac, huffman_tables[2].start, 16 + 162);
-	memcpy(huff_tab->chroma_ac, huffman_tables[3].start, 16 + 162);
+
+	memset(huff_tab, 0, sizeof(*huff_tab));
+	memcpy(huff_tab->luma_dc, huffman_tables[0].start, huffman_tables[0].length);
+	memcpy(huff_tab->chroma_dc, huffman_tables[1].start, huffman_tables[1].length);
+	memcpy(huff_tab->luma_ac, huffman_tables[2].start, huffman_tables[2].length);
+	memcpy(huff_tab->chroma_ac, huffman_tables[3].start, huffman_tables[3].length);
 
 	/* check scan header */
 	for (i = 0; i < scan_header.num_components; i++) {
-- 
2.26.0

Re: [PATCH v2] media: coda: jpeg: support optimized huffman tables

[Philipp Zabel]

On Tue, Mar 24, 2020 at 06:04:29PM +0200, Adrian Ratiu wrote:
> Each jpeg can have the huffman tables optimized for its specific content
> meaning that the table lenghts and values don't match the standard table
> of substitutions so there's no reason to hardcode and expect the standard
> lengths, otherwise we just end up rejecting optimized jpegs altogether.
> 
> Tested on CODA960.
> 
> Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp