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[media] coda: pad first h.264 buffer to 512 bytes

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The bitstream reader needs 512 bytes ready to read to examine the
headers in the first frame. If that frame is too small, prepend it
with a filler NAL.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Philipp Zabel 2017-03-03 09:12:49 -03:00 committed by Mauro Carvalho Chehab
parent 331e7860f3
commit 0eef89403e
3 changed files with 45 additions and 8 deletions
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28
drivers/media/platform/coda/coda-bit.c
View file

@ -179,6 +179,25 @@ static void coda_kfifo_sync_to_device_write(struct coda_ctx *ctx)
coda_write(dev, wr_ptr, CODA_REG_BIT_WR_PTR(ctx->reg_idx));
}
static int coda_bitstream_pad(struct coda_ctx *ctx, u32 size)
{
unsigned char *buf;
u32 n;
if (size < 6)
size = 6;
buf = kmalloc(size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
coda_h264_filler_nal(size, buf);
n = kfifo_in(&ctx->bitstream_fifo, buf, size);
kfree(buf);
return (n < size) ? -ENOSPC : 0;
}
static int coda_bitstream_queue(struct coda_ctx *ctx,
struct vb2_v4l2_buffer *src_buf)
{
@ -198,10 +217,10 @@ static int coda_bitstream_queue(struct coda_ctx *ctx,
static bool coda_bitstream_try_queue(struct coda_ctx *ctx,
struct vb2_v4l2_buffer *src_buf)
{
unsigned long payload = vb2_get_plane_payload(&src_buf->vb2_buf, 0);
int ret;
if (coda_get_bitstream_payload(ctx) +
vb2_get_plane_payload(&src_buf->vb2_buf, 0) + 512 >=
if (coda_get_bitstream_payload(ctx) + payload + 512 >=
ctx->bitstream.size)
return false;
@ -210,6 +229,11 @@ static bool coda_bitstream_try_queue(struct coda_ctx *ctx,
return true;
}
/* Add zero padding before the first H.264 buffer, if it is too small */
if (ctx->qsequence == 0 && payload < 512 &&
ctx->codec->src_fourcc == V4L2_PIX_FMT_H264)
coda_bitstream_pad(ctx, 512 - payload);
ret = coda_bitstream_queue(ctx, src_buf);
if (ret < 0) {
v4l2_err(&ctx->dev->v4l2_dev, "bitstream buffer overflow\n");

24
drivers/media/platform/coda/coda-h264.c
View file

@ -15,10 +15,25 @@
#include <linux/string.h>
#include <coda.h>
static const u8 coda_filler_nal[14] = { 0x00, 0x00, 0x00, 0x01, 0x0c, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x80 };
static const u8 coda_filler_size[8] = { 0, 7, 14, 13, 12, 11, 10, 9 };
int coda_h264_filler_nal(int size, char *p)
{
if (size < 6)
return -EINVAL;
p[0] = 0x00;
p[1] = 0x00;
p[2] = 0x00;
p[3] = 0x01;
p[4] = 0x0c;
memset(p + 5, 0xff, size - 6);
/* Add rbsp stop bit and trailing at the end */
p[size - 1] = 0x80;
return 0;
}
int coda_h264_padding(int size, char *p)
{
int nal_size;
@ -29,10 +44,7 @@ int coda_h264_padding(int size, char *p)
return 0;
nal_size = coda_filler_size[diff];
memcpy(p, coda_filler_nal, nal_size);
/* Add rbsp stop bit and trailing at the end */
*(p + nal_size - 1) = 0x80;
coda_h264_filler_nal(nal_size, p);
return nal_size;
}

1
drivers/media/platform/coda/coda.h
View file

@ -290,6 +290,7 @@ void coda_bit_stream_end_flag(struct coda_ctx *ctx);
void coda_m2m_buf_done(struct coda_ctx *ctx, struct vb2_v4l2_buffer *buf,
enum vb2_buffer_state state);
int coda_h264_filler_nal(int size, char *p);
int coda_h264_padding(int size, char *p);
bool coda_jpeg_check_buffer(struct coda_ctx *ctx, struct vb2_buffer *vb);