Add startcode emulation prevention

[andrey-utkin]

The problem with that particular stream is that you haven't added emulation prevention bytes to escape zeroes, so the decoder is getting confused by occasional sequences that look like start codes. For that stream, there are several glitches in the first 1000 frames, and I was able to manually add the emulation prevention bytes to make it decode without problems.

So, I think that in your driver, in the function:

static void tw5864_handle_frame(struct tw5864_h264_frame *frame)

rather than the stright copy with:

memcpy(dst, frame->vlc.addr + skip_bytes, frame_len);

you want something like:

size_t i, j;
int zero_run;
u8 *src;
...
src = frame->vlc.addr + skip_bytes;
zero_run = 0;
for (i = j = 0; i < frame_len; i++) {
  if (zero_run < 2) {
    if (src[i] == 0)
      ++zero_run;
    else
      zero_run = 0;
  } else {
    if ((src[i] & ~0x03) == 0) {
      dst[j++] = 0x03;
    zero_run = src[i] == 0;
  }
  dst[j++] = src[i];
}