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[media] usbtv: Fix deinterlacing
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The image data is laid out a bit more weirdly and thus needs more work to
properly interlace. What we get from hardware is V4L2_FIELD_ALTERNATE, but
since userspace support for it is practically nonexistent, thus we make
V4L2_FIELD_INTERLACED from it so that it's more easily interpreted.

Signed-off-by: Lubomir Rintel <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
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lkundrak authored and mchehab committed Jul 26, 2013
1 parent 8191328 commit a34caca
Showing 1 changed file with 25 additions and 11 deletions.
36 changes: 25 additions & 11 deletions drivers/media/usb/usbtv/usbtv.c
Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@
#define USBTV_CHUNK_SIZE 256
#define USBTV_CHUNK 240
#define USBTV_CHUNKS (USBTV_WIDTH * USBTV_HEIGHT \
/ 2 / USBTV_CHUNK)
/ 4 / USBTV_CHUNK)

/* Chunk header. */
#define USBTV_MAGIC_OK(chunk) ((be32_to_cpu(chunk[0]) & 0xff000000) \
Expand Down Expand Up @@ -202,6 +202,26 @@ static int usbtv_setup_capture(struct usbtv *usbtv)
return 0;
}

/* Copy data from chunk into a frame buffer, deinterlacing the data
* into every second line. Unfortunately, they don't align nicely into
* 720 pixel lines, as the chunk is 240 words long, which is 480 pixels.
* Therefore, we break down the chunk into two halves before copyting,
* so that we can interleave a line if needed. */
static void usbtv_chunk_to_vbuf(u32 *frame, u32 *src, int chunk_no, int odd)
{
int half;

for (half = 0; half < 2; half++) {
int part_no = chunk_no * 2 + half;
int line = part_no / 3;
int part_index = (line * 2 + !odd) * 3 + (part_no % 3);

u32 *dst = &frame[part_index * USBTV_CHUNK/2];
memcpy(dst, src, USBTV_CHUNK/2 * sizeof(*src));
src += USBTV_CHUNK/2;
}
}

/* Called for each 256-byte image chunk.
* First word identifies the chunk, followed by 240 words of image
* data and padding. */
Expand All @@ -218,11 +238,6 @@ static void usbtv_image_chunk(struct usbtv *usbtv, u32 *chunk)
frame_id = USBTV_FRAME_ID(chunk);
odd = USBTV_ODD(chunk);
chunk_no = USBTV_CHUNK_NO(chunk);

/* Deinterlace. TODO: Use interlaced frame format. */
chunk_no = (chunk_no - chunk_no % 3) * 2 + chunk_no % 3;
chunk_no += !odd * 3;

if (chunk_no >= USBTV_CHUNKS)
return;

Expand All @@ -241,12 +256,11 @@ static void usbtv_image_chunk(struct usbtv *usbtv, u32 *chunk)
buf = list_first_entry(&usbtv->bufs, struct usbtv_buf, list);
frame = vb2_plane_vaddr(&buf->vb, 0);

/* Copy the chunk. */
memcpy(&frame[chunk_no * USBTV_CHUNK], &chunk[1],
USBTV_CHUNK * sizeof(chunk[1]));
/* Copy the chunk data. */
usbtv_chunk_to_vbuf(frame, &chunk[1], chunk_no, odd);

/* Last chunk in a frame, signalling an end */
if (usbtv->frame_id && chunk_no == USBTV_CHUNKS-1) {
if (odd && chunk_no == USBTV_CHUNKS-1) {
int size = vb2_plane_size(&buf->vb, 0);

buf->vb.v4l2_buf.field = V4L2_FIELD_INTERLACED;
Expand Down Expand Up @@ -518,7 +532,7 @@ static int usbtv_queue_setup(struct vb2_queue *vq,
if (*nbuffers < 2)
*nbuffers = 2;
*nplanes = 1;
sizes[0] = USBTV_CHUNK * USBTV_CHUNKS * sizeof(u32);
sizes[0] = USBTV_WIDTH * USBTV_HEIGHT / 2 * sizeof(u32);

return 0;
}
Expand Down

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