Em Mon, 29 Oct 2012 13:34:59 +0100
javier.martin@xxxxxxxxxxxxxxxxx escreveu:
> From: Javier Martin <javier.martin@xxxxxxxxxxxxxxxxx>
>
> Length of H.264 headers is variable and thus it might not be
> aligned for the coda to append the encoded frame. This causes
> the first frame to overwrite part of the H.264 PPS.
>
> In order to solve that, a filler NAL must be added between
> the headers and the first frame to preserve alignment.
>
> Signed-off-by: Javier Martin <javier.martin@xxxxxxxxxxxxxxxxx>
Please next time check it with checkpatch.pl.
Also, please send us a patch adding yourself at MAINTAINERS for this
driver.
Regards,
Mauro
> ---
> Changes since v1:
> - Align to 64bits as requested by Philipp.
>
> ---
> drivers/media/platform/coda.c | 30 +++++++++++++++++++++++++++++-
> 1 file changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/coda.c b/drivers/media/platform/coda.c
> index a8c7a94..7febcd9 100644
> --- a/drivers/media/platform/coda.c
> +++ b/drivers/media/platform/coda.c
> @@ -177,6 +177,10 @@ struct coda_ctx {
> int idx;
> };
>
> +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 };
> +
> static inline void coda_write(struct coda_dev *dev, u32 data, u32 reg)
> {
> v4l2_dbg(1, coda_debug, &dev->v4l2_dev,
> @@ -938,6 +942,24 @@ static int coda_alloc_framebuffers(struct coda_ctx *ctx, struct coda_q_data *q_d
> return 0;
> }
>
> +static int coda_h264_padding(int size, char *p)
> +{
> + int nal_size;
> + int diff;
> +
> + diff = size - (size & ~0x7);
> + if (diff == 0)
> + 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;
> +
> + return nal_size;
> +}
> +
> static int coda_start_streaming(struct vb2_queue *q, unsigned int count)
> {
> struct coda_ctx *ctx = vb2_get_drv_priv(q);
> @@ -1165,7 +1187,13 @@ static int coda_start_streaming(struct vb2_queue *q, unsigned int count)
> coda_read(dev, CODA_CMD_ENC_HEADER_BB_START);
> memcpy(&ctx->vpu_header[1][0], vb2_plane_vaddr(buf, 0),
> ctx->vpu_header_size[1]);
> - ctx->vpu_header_size[2] = 0;
> + /*
> + * Length of H.264 headers is variable and thus it might not be
> + * aligned for the coda to append the encoded frame. In that is
> + * the case a filler NAL must be added to header 2.
> + */
> + ctx->vpu_header_size[2] = coda_h264_padding((ctx->vpu_header_size[0] +
> + ctx->vpu_header_size[1]), ctx->vpu_header[2]);
> break;
> case V4L2_PIX_FMT_MPEG4:
> /*
Cheers,
Mauro
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