From 3f3f5c7f63dec5d6413075116cd6beee1e888d7b Mon Sep 17 00:00:00 2001 From: Javier Martin Date: Mon, 29 Oct 2012 05:20:29 -0300 Subject: [PATCH] [media] media: coda: Fix H.264 header alignment 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. [mchehab@redhat.com: Fix a few CodingStyle issues] Signed-off-by: Javier Martin Signed-off-by: Mauro Carvalho Chehab --- drivers/media/platform/coda.c | 36 ++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/coda.c b/drivers/media/platform/coda.c index 7b8b547f2d51..8b7f5ac7fc11 100644 --- a/drivers/media/platform/coda.c +++ b/drivers/media/platform/coda.c @@ -178,6 +178,9 @@ struct coda_ctx { int idx; }; +static u8 coda_filler_nal[] = { 0x00, 0x00, 0x00, 0x01, 0x0c, + 0xff, 0xff, 0xff, 0xff, 0xff}; + static inline void coda_write(struct coda_dev *dev, u32 data, u32 reg) { v4l2_dbg(1, coda_debug, &dev->v4l2_dev, @@ -944,6 +947,29 @@ 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 size_align = size & ~0x3; + int filler_size = ARRAY_SIZE(coda_filler_nal); + int nal_size; + int diff; + + diff = size - size_align; + if (diff == 0) + return 0; + + nal_size = filler_size + 2 - diff; + if (nal_size > filler_size) + nal_size -= 4; + + 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); @@ -1171,7 +1197,15 @@ 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: /* -- 2.39.5