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Commit 25738cbd authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
Browse files

[media] uvcvideo: Extract timestamp-related statistics 



Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 7bc5edb0

drivers/media/video/uvc/uvc_video.c

+123 −2
Original line number Diff line number Diff line
@@ -365,6 +365,11 @@ static void uvc_video_stats_decode(struct uvc_streaming *stream, 
		const __u8 *data, int len)

{

	unsigned int header_size;

	bool has_pts = false;

	bool has_scr = false;

	u16 uninitialized_var(scr_sof);

	u32 uninitialized_var(scr_stc);

	u32 uninitialized_var(pts);



	if (stream->stats.stream.nb_frames == 0 &&

	    stream->stats.frame.nb_packets == 0)
@@ -373,12 +378,16 @@ static void uvc_video_stats_decode(struct uvc_streaming *stream, 
	switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {

	case UVC_STREAM_PTS | UVC_STREAM_SCR:

		header_size = 12;

		has_pts = true;

		has_scr = true;

		break;

	case UVC_STREAM_PTS:

		header_size = 6;

		has_pts = true;

		break;

	case UVC_STREAM_SCR:

		header_size = 8;

		has_scr = true;

		break;

	default:

		header_size = 2;
@@ -391,6 +400,63 @@ static void uvc_video_stats_decode(struct uvc_streaming *stream, 
		return;

	}



	/* Extract the timestamps. */

	if (has_pts)

		pts = get_unaligned_le32(&data[2]);



	if (has_scr) {

		scr_stc = get_unaligned_le32(&data[header_size - 6]);

		scr_sof = get_unaligned_le16(&data[header_size - 2]);

	}



	/* Is PTS constant through the whole frame ? */

	if (has_pts && stream->stats.frame.nb_pts) {

		if (stream->stats.frame.pts != pts) {

			stream->stats.frame.nb_pts_diffs++;

			stream->stats.frame.last_pts_diff =

				stream->stats.frame.nb_packets;

		}

	}



	if (has_pts) {

		stream->stats.frame.nb_pts++;

		stream->stats.frame.pts = pts;

	}



	/* Do all frames have a PTS in their first non-empty packet, or before

	 * their first empty packet ?

	 */

	if (stream->stats.frame.size == 0) {

		if (len > header_size)

			stream->stats.frame.has_initial_pts = has_pts;

		if (len == header_size && has_pts)

			stream->stats.frame.has_early_pts = true;

	}



	/* Do the SCR.STC and SCR.SOF fields vary through the frame ? */

	if (has_scr && stream->stats.frame.nb_scr) {

		if (stream->stats.frame.scr_stc != scr_stc)

			stream->stats.frame.nb_scr_diffs++;

	}



	if (has_scr) {

		/* Expand the SOF counter to 32 bits and store its value. */

		if (stream->stats.stream.nb_frames > 0 ||

		    stream->stats.frame.nb_scr > 0)

			stream->stats.stream.scr_sof_count +=

				(scr_sof - stream->stats.stream.scr_sof) % 2048;

		stream->stats.stream.scr_sof = scr_sof;



		stream->stats.frame.nb_scr++;

		stream->stats.frame.scr_stc = scr_stc;

		stream->stats.frame.scr_sof = scr_sof;



		if (scr_sof < stream->stats.stream.min_sof)

			stream->stats.stream.min_sof = scr_sof;

		if (scr_sof > stream->stats.stream.max_sof)

			stream->stats.stream.max_sof = scr_sof;

	}



	/* Record the first non-empty packet number. */

	if (stream->stats.frame.size == 0 && len > header_size)

		stream->stats.frame.first_data = stream->stats.frame.nb_packets;
@@ -411,9 +477,16 @@ static void uvc_video_stats_update(struct uvc_streaming *stream) 
{

	struct uvc_stats_frame *frame = &stream->stats.frame;



	uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets\n",

	uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets, "

		  "%u/%u/%u pts (%searly %sinitial), %u/%u scr, "

		  "last pts/stc/sof %u/%u/%u\n",

		  stream->sequence, frame->first_data,

		  frame->nb_packets - frame->nb_empty, frame->nb_packets);

		  frame->nb_packets - frame->nb_empty, frame->nb_packets,

		  frame->nb_pts_diffs, frame->last_pts_diff, frame->nb_pts,

		  frame->has_early_pts ? "" : "!",

		  frame->has_initial_pts ? "" : "!",

		  frame->nb_scr_diffs, frame->nb_scr,

		  frame->pts, frame->scr_stc, frame->scr_sof);



	stream->stats.stream.nb_frames++;

	stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
@@ -421,14 +494,47 @@ static void uvc_video_stats_update(struct uvc_streaming *stream) 
	stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;

	stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;



	if (frame->has_early_pts)

		stream->stats.stream.nb_pts_early++;

	if (frame->has_initial_pts)

		stream->stats.stream.nb_pts_initial++;

	if (frame->last_pts_diff <= frame->first_data)

		stream->stats.stream.nb_pts_constant++;

	if (frame->nb_scr >= frame->nb_packets - frame->nb_empty)

		stream->stats.stream.nb_scr_count_ok++;

	if (frame->nb_scr_diffs + 1 == frame->nb_scr)

		stream->stats.stream.nb_scr_diffs_ok++;



	memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));

}



size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,

			    size_t size)

{

	unsigned int scr_sof_freq;

	unsigned int duration;

	struct timespec ts;

	size_t count = 0;



	ts.tv_sec = stream->stats.stream.stop_ts.tv_sec

		  - stream->stats.stream.start_ts.tv_sec;

	ts.tv_nsec = stream->stats.stream.stop_ts.tv_nsec

		   - stream->stats.stream.start_ts.tv_nsec;

	if (ts.tv_nsec < 0) {

		ts.tv_sec--;

		ts.tv_nsec += 1000000000;

	}



	/* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF

	 * frequency this will not overflow before more than 1h.

	 */

	duration = ts.tv_sec * 1000 + ts.tv_nsec / 1000000;

	if (duration != 0)

		scr_sof_freq = stream->stats.stream.scr_sof_count * 1000

			     / duration;

	else

		scr_sof_freq = 0;



	count += scnprintf(buf + count, size - count,

			   "frames:  %u\npackets: %u\nempty:   %u\n"

			   "errors:  %u\ninvalid: %u\n",
@@ -437,6 +543,20 @@ size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf, 
			   stream->stats.stream.nb_empty,

			   stream->stats.stream.nb_errors,

			   stream->stats.stream.nb_invalid);

	count += scnprintf(buf + count, size - count,

			   "pts: %u early, %u initial, %u ok\n",

			   stream->stats.stream.nb_pts_early,

			   stream->stats.stream.nb_pts_initial,

			   stream->stats.stream.nb_pts_constant);

	count += scnprintf(buf + count, size - count,

			   "scr: %u count ok, %u diff ok\n",

			   stream->stats.stream.nb_scr_count_ok,

			   stream->stats.stream.nb_scr_diffs_ok);

	count += scnprintf(buf + count, size - count,

			   "sof: %u <= sof <= %u, freq %u.%03u kHz\n",

			   stream->stats.stream.min_sof,

			   stream->stats.stream.max_sof,

			   scr_sof_freq / 1000, scr_sof_freq % 1000);



	return count;

}
@@ -444,6 +564,7 @@ size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf, 
static void uvc_video_stats_start(struct uvc_streaming *stream)

{

	memset(&stream->stats, 0, sizeof(stream->stats));

	stream->stats.stream.min_sof = 2048;

}



static void uvc_video_stats_stop(struct uvc_streaming *stream)

drivers/media/video/uvc/uvcvideo.h

+23 −0
Original line number Diff line number Diff line
@@ -364,6 +364,18 @@ struct uvc_stats_frame { 
	unsigned int nb_empty;		/* Number of empty packets */

	unsigned int nb_invalid;	/* Number of packets with an invalid header */

	unsigned int nb_errors;		/* Number of packets with the error bit set */



	unsigned int nb_pts;		/* Number of packets with a PTS timestamp */

	unsigned int nb_pts_diffs;	/* Number of PTS differences inside a frame */

	unsigned int last_pts_diff;	/* Index of the last PTS difference */

	bool has_initial_pts;		/* Whether the first non-empty packet has a PTS */

	bool has_early_pts;		/* Whether a PTS is present before the first non-empty packet */

	u32 pts;			/* PTS of the last packet */



	unsigned int nb_scr;		/* Number of packets with a SCR timestamp */

	unsigned int nb_scr_diffs;	/* Number of SCR.STC differences inside a frame */

	u16 scr_sof;			/* SCR.SOF of the last packet */

	u32 scr_stc;			/* SCR.STC of the last packet */

};



struct uvc_stats_stream {
@@ -376,6 +388,17 @@ struct uvc_stats_stream { 
	unsigned int nb_empty;		/* Number of empty packets */

	unsigned int nb_invalid;	/* Number of packets with an invalid header */

	unsigned int nb_errors;		/* Number of packets with the error bit set */



	unsigned int nb_pts_constant;	/* Number of frames with constant PTS */

	unsigned int nb_pts_early;	/* Number of frames with early PTS */

	unsigned int nb_pts_initial;	/* Number of frames with initial PTS */



	unsigned int nb_scr_count_ok;	/* Number of frames with at least one SCR per non empty packet */

	unsigned int nb_scr_diffs_ok;	/* Number of frames with varying SCR.STC */

	unsigned int scr_sof_count;	/* STC.SOF counter accumulated since stream start */

	unsigned int scr_sof;		/* STC.SOF of the last packet */

	unsigned int min_sof;		/* Minimum STC.SOF value */

	unsigned int max_sof;		/* Maximum STC.SOF value */

};



struct uvc_streaming {