bluecherrydvr / linux Goto Github PK

tw5864 driver was submitted for review and inclusion into mainline kernel. Got a bunch of things to fix. Need to work on that and resubmit.

One of #ffmpeg IRC guys, jkqxz, agreed to consult me regarding correctness of stream (decoding errors and such). Need to provide him with latest samples of problematic videos for analysis.

When our kernel .deb package is installed on a host where previous our kernel package is already installed, there's such error which fails the installations:
trying to overwrite '/etc/modules-load.d/tw5864.conf'
So user must remove previous package to install new one.

dkms solo driver panic

kernel BUG at /build/buildd/linux-3.2.0/drivers/media/video/videobuf-dma-sg.c:525!
invalid opcode: 0000 SMP

On customer's installation (Mr. Luna) some cameras which are said to provide good picture previously, have noisy picture. No idea how to improve that. Maybe we could analyze decoding errors if there are any.

Set constraint_set1_flag even though spec doesn't say it, because the output does conform to constrained baseline profile and setting it can only improve compatibility.

(From consultant)

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];
}