Index | Thread | Search

From:
Marcus Glocker <marcus@nazgul.ch>
Subject:
Re: sys/uvideo: support H.264 format and frame
To:
"Kirill A. Korinsky" <kirill@korins.ky>
Cc:
tech@openbsd.org
Date:
Sun, 3 Aug 2025 10:03:17 +0200

Download raw body.

Thread
On Sat, Aug 02, 2025 at 01:18:19PM +0200, Kirill A. Korinsky wrote:

> On Sat, 02 Aug 2025 01:07:59 +0200,
> Kirill A. Korinsky <kirill@korins.ky> wrote:
> > 
> > tech@,
> > 
> > here a diff which brings support of H.264 stream from webcam.
> > 
> > Tested on Elgato Facecam Pro.
> > 
> > Also tested as raw and mjpeg against:
> >  - Elgato Facecam Pro
> >  - Jabra PanaCast 20
> >  - Azurewave, USB camera
> > 
> > No regression discovered.
> > 
> 
> Here a bit cleaner version. Changes only related to UVIDEO_FRAME_MIN_LEN and
> UVIDEO_FRAME_H264_MIN_LEN, I've replaced a constant by offsetof and sizeof.
> 
> Ok?

The diff looks good to me.  No regressions noticed during quick testing.

ok mglocker@

When reviewing the diff I've noticed that we might could do some small
improvements regarding the structure sizes in a second step:

- We probably should define an union structure within a packed structure
  also with '__packed', like other drivers are doing it.  I'm not sure
  depending on the compiler/architecture whether otherwise an union
  structure could be interpreted as non-packed.  Maybe other developers
  can comment on their opinion about that.

- The constant integers used in uvideo_vs_parse_desc_format() for the
  format structure sizes should be all replaced by defines in uvideo.h:

	desc->bLength == 6
	desc->bLength == 11
	desc->bLength == 27
	desc->bLength == 52
 
> Index: sys/dev/usb/uvideo.c
> ===================================================================
> RCS file: /home/cvs/src/sys/dev/usb/uvideo.c,v
> diff -u -p -r1.258 uvideo.c
> --- sys/dev/usb/uvideo.c	19 Apr 2025 19:35:32 -0000	1.258
> +++ sys/dev/usb/uvideo.c	1 Aug 2025 22:53:22 -0000
> @@ -132,11 +132,15 @@ usbd_status	uvideo_vs_parse_desc_input_h
>  usbd_status	uvideo_vs_parse_desc_format(struct uvideo_softc *);
>  usbd_status	uvideo_vs_parse_desc_colorformat(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
> +usbd_status	uvideo_vs_parse_desc_format_h264(struct uvideo_softc *,
> +		    const usb_descriptor_t *);
>  usbd_status	uvideo_vs_parse_desc_format_mjpeg(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
>  usbd_status	uvideo_vs_parse_desc_format_uncompressed(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
>  usbd_status	uvideo_vs_parse_desc_frame(struct uvideo_softc *);
> +usbd_status	uvideo_vs_parse_desc_frame_h264(struct uvideo_softc *,
> +		    const usb_descriptor_t *);
>  usbd_status	uvideo_vs_parse_desc_frame_sub(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
>  uint32_t	uvideo_vc_parse_max_packet_size(struct uvideo_softc *,
> @@ -210,8 +214,12 @@ void		uvideo_dump_desc_format_mjpeg(stru
>  		    const usb_descriptor_t *);
>  void		uvideo_dump_desc_format_uncompressed(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
> +void		uvideo_dump_desc_format_h264(struct uvideo_softc *,
> +		    const usb_descriptor_t *);
>  void		uvideo_dump_desc_frame(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
> +void		uvideo_dump_desc_h264_frame(struct uvideo_softc *,
> +		    const usb_descriptor_t *);
>  void		uvideo_dump_desc_processing(struct uvideo_softc *,
>  		    const usb_descriptor_t *);
>  void		uvideo_dump_desc_extension(struct uvideo_softc *,
> @@ -738,10 +746,8 @@ uvideo_vc_parse_desc(struct uvideo_softc
>  			break;
>  		case UDESCSUB_VC_PROCESSING_UNIT:
>  			/* XXX do correct length calculation */
> -			if (desc->bLength <
> -			    sizeof(struct usb_video_frame_desc)) {
> +			if (desc->bLength < UVIDEO_FRAME_MIN_LEN)
>  				(void)uvideo_vc_parse_desc_pu(sc, desc);
> -			}
>  			break;
>  
>  		/* TODO: which VC descriptors do we need else? */
> @@ -1058,6 +1064,13 @@ uvideo_vs_parse_desc_format(struct uvide
>  				    sc, desc);
>  			}
>  			break;
> +		case UDESCSUB_VS_FORMAT_H264:
> +		case UDESCSUB_VS_FORMAT_H264_SIMULCAST:
> +			if (desc->bLength == 52) {
> +				(void)uvideo_vs_parse_desc_format_h264(
> +				    sc, desc);
> +			}
> +			break;
>  		}
>  
>  		desc = usbd_desc_iter_next(&iter);
> @@ -1153,6 +1166,47 @@ uvideo_vs_parse_desc_format_mjpeg(struct
>  }
>  
>  usbd_status
> +uvideo_vs_parse_desc_format_h264(struct uvideo_softc *sc,
> +    const usb_descriptor_t *desc)
> +{
> +	struct usb_video_format_h264_desc *d;
> +
> +	d = (struct usb_video_format_h264_desc *)(uint8_t *)desc;
> +
> +	if (d->bNumFrameDescriptors == 0) {
> +		printf("%s: no H.264 frame descriptors available!\n",
> +		    DEVNAME(sc));
> +		return (USBD_INVAL);
> +	}
> +
> +	if (sc->sc_fmtgrp_idx >= UVIDEO_MAX_FORMAT) {
> +		printf("%s: too many format descriptors found!\n", DEVNAME(sc));
> +		return (USBD_INVAL);
> +	}
> +
> +	sc->sc_fmtgrp[sc->sc_fmtgrp_idx].format =
> +	    (struct uvideo_format_desc *)d;
> +	if (d->bDefaultFrameIndex > d->bNumFrameDescriptors ||
> +	    d->bDefaultFrameIndex < 1) {
> +		/* sanitize wrong bDefaultFrameIndex value */
> +		sc->sc_fmtgrp[sc->sc_fmtgrp_idx].format_dfidx = 1;
> +	} else {
> +		sc->sc_fmtgrp[sc->sc_fmtgrp_idx].format_dfidx =
> +		    d->bDefaultFrameIndex;
> +	}
> +	sc->sc_fmtgrp[sc->sc_fmtgrp_idx].pixelformat = V4L2_PIX_FMT_H264;
> +
> +	if (sc->sc_fmtgrp_cur == NULL)
> +		/* set H.264 format */
> +		sc->sc_fmtgrp_cur = &sc->sc_fmtgrp[sc->sc_fmtgrp_idx];
> +
> +	sc->sc_fmtgrp_idx++;
> +	sc->sc_fmtgrp_num++;
> +
> +	return (USBD_NORMAL_COMPLETION);
> +}
> +
> +usbd_status
>  uvideo_vs_parse_desc_format_uncompressed(struct uvideo_softc *sc,
>      const usb_descriptor_t *desc)
>  {
> @@ -1236,13 +1290,20 @@ uvideo_vs_parse_desc_frame(struct uvideo
>  		if (desc->bDescriptorType == UDESC_IFACE_ASSOC)
>  			break;
>  		if (desc->bDescriptorType == UDESC_CS_INTERFACE &&
> -		    desc->bLength > sizeof(struct usb_video_frame_desc) &&
> +		    desc->bLength > UVIDEO_FRAME_MIN_LEN &&
>  		    (desc->bDescriptorSubtype == UDESCSUB_VS_FRAME_MJPEG ||
>  		    desc->bDescriptorSubtype == UDESCSUB_VS_FRAME_UNCOMPRESSED)) {
>  			error = uvideo_vs_parse_desc_frame_sub(sc, desc);
>  			if (error != USBD_NORMAL_COMPLETION)
>  				return (error);
>  		}
> +		if (desc->bDescriptorType == UDESC_CS_INTERFACE &&
> +		    desc->bLength > UVIDEO_FRAME_H264_MIN_LEN &&
> +		    desc->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264) {
> +			error = uvideo_vs_parse_desc_frame_h264(sc, desc);
> +			if (error != USBD_NORMAL_COMPLETION)
> +				return (error);
> +		}
>  		desc = usbd_desc_iter_next(&iter);
>  	}
>  
> @@ -1282,14 +1343,79 @@ uvideo_vs_parse_desc_frame_sub(struct uv
>  	 * Bytes per pixel can vary with compressed formats.
>  	 */
>  	if (desc->bDescriptorSubtype == UDESCSUB_VS_FRAME_UNCOMPRESSED) {
> -		fbuf_size = UGETW(fd->wWidth) * UGETW(fd->wHeight) *
> +		fbuf_size = UGETW(fd->u.d.wWidth) * UGETW(fd->u.d.wHeight) *
>  		    sc->sc_fmtgrp[fmtidx].format->u.uc.bBitsPerPixel / NBBY;
>  		DPRINTF(10, "%s: %s: frame buffer size=%d "
>  		    "width=%d height=%d bpp=%d\n", DEVNAME(sc), __func__,
> -		    fbuf_size, UGETW(fd->wWidth), UGETW(fd->wHeight),
> +		    fbuf_size, UGETW(fd->u.d.wWidth), UGETW(fd->u.d.wHeight),
>  		    sc->sc_fmtgrp[fmtidx].format->u.uc.bBitsPerPixel);
>  	} else
> -		fbuf_size = UGETDW(fd->dwMaxVideoFrameBufferSize);
> +		fbuf_size = UGETDW(fd->u.d.dwMaxVideoFrameBufferSize);
> +
> +	/* store max value */
> +	if (fbuf_size > sc->sc_max_fbuf_size)
> +		sc->sc_max_fbuf_size = fbuf_size;
> +
> +	/*
> +	 * Increment frame count.  If this is the last frame in the
> +	 * format group, go on to next group.
> +	 */
> +	if (++sc->sc_fmtgrp[fmtidx].frame_num ==
> +	    sc->sc_fmtgrp[fmtidx].format->bNumFrameDescriptors) {
> +		sc->sc_fmtgrp_idx++;
> +	}
> +
> +	return (USBD_NORMAL_COMPLETION);
> +}
> +
> +usbd_status
> +uvideo_vs_parse_desc_frame_h264(struct uvideo_softc *sc,
> +    const usb_descriptor_t *desc)
> +{
> +	struct usb_video_frame_desc *fd =
> +	    (struct usb_video_frame_desc *)(uint8_t *)desc;
> +	uint8_t *p;
> +	int i, fmtidx, frame_num, length;
> +	uint32_t fbuf_size, frame_ival, next_frame_ival;
> +
> +	fmtidx = sc->sc_fmtgrp_idx;
> +	frame_num = sc->sc_fmtgrp[fmtidx].frame_num;
> +	if (frame_num >= UVIDEO_MAX_FRAME) {
> +		printf("%s: too many H.264 frame descriptors found!\n",
> +		    DEVNAME(sc));
> +		return (USBD_INVAL);
> +	}
> +	sc->sc_fmtgrp[fmtidx].frame[frame_num] = fd;
> +
> +	if (sc->sc_fmtgrp[fmtidx].frame_cur == NULL ||
> +	    sc->sc_fmtgrp[fmtidx].format_dfidx == fd->bFrameIndex)
> +		sc->sc_fmtgrp[fmtidx].frame_cur = fd;
> +
> +	/*
> +	 * H.264 frame hasn't got dwMaxVideoFrameBufferSize, instead
> +	 * compute requiers buffer via dwMaxBitRate and dwFrameInterval.
> +	 */
> +
> +	frame_ival = UGETDW(fd->u.h264.dwDefaultFrameInterval);
> +
> +	p = (uint8_t *)desc;
> +	p += UVIDEO_FRAME_H264_MIN_LEN;
> +	length = fd->bLength - UVIDEO_FRAME_H264_MIN_LEN;
> +
> +	for (i = 0; i < fd->u.h264.bNumFrameIntervals; i++) {
> +		if (length <= 0) {
> +			printf("frame descriptor ended early\n");
> +			break;
> +		}
> +		next_frame_ival = UGETDW(p);
> +		if (next_frame_ival > frame_ival)
> +			frame_ival = next_frame_ival;
> +		p += sizeof(uDWord);
> +		length -= sizeof(uDWord);
> +	}
> +
> +	fbuf_size = UGETDW(fd->u.h264.dwMaxBitRate) * frame_ival;
> +	fbuf_size /= 8 * 10000000;
>  
>  	/* store max value */
>  	if (fbuf_size > sc->sc_max_fbuf_size)
> @@ -1574,12 +1700,19 @@ uvideo_find_res(struct uvideo_softc *sc,
>      struct uvideo_res *r)
>  {
>  	int i, w, h, diff, diff_best, size_want, size_is;
> +	struct usb_video_frame_desc *frame;
>  
>  	size_want = width * height;
>  
>  	for (i = 0; i < sc->sc_fmtgrp[idx].frame_num; i++) {
> -		w = UGETW(sc->sc_fmtgrp[idx].frame[i]->wWidth);
> -		h = UGETW(sc->sc_fmtgrp[idx].frame[i]->wHeight);
> +		frame = sc->sc_fmtgrp[idx].frame[i];
> +		if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264) {
> +			w = UGETW(frame->u.h264.wWidth);
> +			h = UGETW(frame->u.h264.wHeight);
> +		} else {
> +			w = UGETW(frame->u.d.wWidth);
> +			h = UGETW(frame->u.d.wHeight);
> +		}
>  		size_is = w * h;
>  		if (size_is > size_want)
>  			diff = size_is - size_want;
> @@ -1610,6 +1743,7 @@ uvideo_vs_negotiation(struct uvideo_soft
>  	uint32_t frame_ival, nivals, min, max, step, diff;
>  	usbd_status error;
>  	int i, ival_bytes, changed = 0;
> +	size_t len;
>  
>  	pc = (struct usb_video_probe_commit *)probe_data;
>  
> @@ -1629,15 +1763,24 @@ uvideo_vs_negotiation(struct uvideo_soft
>  	pc->bFormatIndex = fmtgrp->format->bFormatIndex;
>  	pc->bFrameIndex = fmtgrp->frame_cur->bFrameIndex;
>  	/* dwFrameInterval: 30fps=333333, 15fps=666666, 10fps=1000000 */
> -	frame_ival = UGETDW(fmtgrp->frame_cur->dwDefaultFrameInterval);
> +	frame = fmtgrp->frame_cur;
> +	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264)
> +		frame_ival = UGETDW(frame->u.h264.dwDefaultFrameInterval);
> +	else
> +		frame_ival = UGETDW(frame->u.d.dwDefaultFrameInterval);
>  	if (sc->sc_frame_rate != 0) {
>  		frame_ival = 10000000 / sc->sc_frame_rate;
>  		/* find closest matching interval the device supports */
> +		if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264) {
> +			len = UVIDEO_FRAME_H264_MIN_LEN;
> +			nivals = 0;
> +		} else {
> +			len = UVIDEO_FRAME_MIN_LEN;
> +			nivals = frame->u.d.bFrameIntervalType;
> +		}
>  		p = (uint8_t *)fmtgrp->frame_cur;
> -		p += sizeof(struct usb_video_frame_desc);
> -		nivals = fmtgrp->frame_cur->bFrameIntervalType;
> -		ival_bytes = fmtgrp->frame_cur->bLength -
> -		    sizeof(struct usb_video_frame_desc);
> +		p += len;
> +		ival_bytes = frame->bLength - len;
>  		if (!nivals && (ival_bytes >= sizeof(uDWord) * 3)) {
>  			/* continuous */
>  			min = UGETDW(p);
> @@ -1737,12 +1880,12 @@ uvideo_vs_negotiation(struct uvideo_soft
>  	 */
>  	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_UNCOMPRESSED) {
>  		USETDW(pc->dwMaxVideoFrameSize,
> -		    UGETW(frame->wWidth) * UGETW(frame->wHeight) *
> +		    UGETW(frame->u.d.wWidth) * UGETW(frame->u.d.wHeight) *
>  		    fmtgrp->format->u.uc.bBitsPerPixel / NBBY);
>  		DPRINTF(1, "fixed dwMaxVideoFrameSize=%d, "
>  		    "width=%d height=%d bpp=%d\n",
>  		    UGETDW(pc->dwMaxVideoFrameSize),
> -		    UGETW(frame->wWidth), UGETW(frame->wHeight),
> +		    UGETW(frame->u.d.wWidth), UGETW(frame->u.d.wHeight),
>  		    fmtgrp->format->u.uc.bBitsPerPixel);
>  	} else {
>  		/*
> @@ -1754,8 +1897,8 @@ uvideo_vs_negotiation(struct uvideo_soft
>  		    UGETW(hd->bcdUVC) < 0x0110 ) {
>  			DPRINTF(1, "%s: dwMaxVideoFrameSize == 0, fixed\n",
>  			    DEVNAME(sc));
> -			USETDW(pc->dwMaxVideoFrameSize, 
> -			    UGETDW(frame->dwMaxVideoFrameBufferSize));
> +			USETDW(pc->dwMaxVideoFrameSize,
> +			    UGETDW(frame->u.d.dwMaxVideoFrameBufferSize));
>  		}
>  	}
>  
> @@ -2664,8 +2807,7 @@ uvideo_dump_desc_all(struct uvideo_softc
>  			case UDESCSUB_VC_PROCESSING_UNIT:
>  				printf("bDescriptorSubtype=0x%02x",
>  				    desc->bDescriptorSubtype);
> -				if (desc->bLength >
> -				    sizeof(struct usb_video_frame_desc)) {
> +				if (desc->bLength > UVIDEO_FRAME_MIN_LEN) {
>  					printf(" (UDESCSUB_VS_FRAME_"
>  					    "UNCOMPRESSED)\n");
>  					uvideo_dump_desc_frame(sc, desc);
> @@ -2694,12 +2836,38 @@ uvideo_dump_desc_all(struct uvideo_softc
>  				printf("bDescriptorSubtype=0x%02x",
>  				    desc->bDescriptorSubtype);
>  				printf(" (UDESCSUB_VS_FRAME_MJPEG)\n");
> -				if (desc->bLength >
> -				    sizeof(struct usb_video_frame_desc)) {
> +				if (desc->bLength > UVIDEO_FRAME_MIN_LEN) {
>  					printf("|\n");
>  					uvideo_dump_desc_frame(sc, desc);
>  				}
>  				break;
> +			case UDESCSUB_VS_FORMAT_H264:
> +				printf("bDescriptorSubtype=0x%02x",
> +				    desc->bDescriptorSubtype);
> +				printf(" (UDESCSUB_VS_FORMAT_H264)\n");
> +				if (desc->bLength == 52) {
> +					printf("|\n");
> +					uvideo_dump_desc_format_h264(sc, desc);
> +				}
> +				break;
> +			case UDESCSUB_VS_FRAME_H264:
> +				printf("bDescriptorSubtype=0x%02x",
> +				    desc->bDescriptorSubtype);
> +				printf(" (UDESCSUB_VS_FRAME_H264)\n");
> +				if (desc->bLength > UVIDEO_FRAME_H264_MIN_LEN) {
> +					printf("|\n");
> +					uvideo_dump_desc_h264_frame(sc, desc);
> +				}
> +				break;
> +			case UDESCSUB_VS_FORMAT_H264_SIMULCAST:
> +				printf("bDescriptorSubtype=0x%02x",
> +				    desc->bDescriptorSubtype);
> +				printf(" (UDESCSUB_VS_FORMAT_H264_SIMULCAST)\n");
> +				if (desc->bLength == 52) {
> +					printf("|\n");
> +					uvideo_dump_desc_format_h264(sc, desc);
> +				}
> +				break;
>  			case UDESCSUB_VS_COLORFORMAT:
>  				printf("bDescriptorSubtype=0x%02x",
>  				   desc->bDescriptorSubtype);
> @@ -2989,6 +3157,7 @@ uvideo_dump_desc_colorformat(struct uvid
>  	    d->bTransferCharacteristics);
>  	printf("bMatrixCoefficients=0x%02x\n", d->bMatrixCoefficients);
>  }
> +
>  void
>  uvideo_dump_desc_format_mjpeg(struct uvideo_softc *sc,
>      const usb_descriptor_t *desc)
> @@ -3023,24 +3192,24 @@ uvideo_dump_desc_frame(struct uvideo_sof
>  	printf("bDescriptorType=0x%02x\n", d->bDescriptorType);
>  	printf("bDescriptorSubtype=0x%02x\n", d->bDescriptorSubtype);
>  	printf("bFrameIndex=0x%02x\n", d->bFrameIndex);
> -	printf("bmCapabilities=0x%02x\n", d->bmCapabilities);
> -	printf("wWidth=%d\n", UGETW(d->wWidth));
> -	printf("wHeight=%d\n", UGETW(d->wHeight));
> -	printf("dwMinBitRate=%d\n", UGETDW(d->dwMinBitRate));
> -	printf("dwMaxBitRate=%d\n", UGETDW(d->dwMaxBitRate));
> +	printf("bmCapabilities=0x%02x\n", d->u.d.bmCapabilities);
> +	printf("wWidth=%d\n", UGETW(d->u.d.wWidth));
> +	printf("wHeight=%d\n", UGETW(d->u.d.wHeight));
> +	printf("dwMinBitRate=%d\n", UGETDW(d->u.d.dwMinBitRate));
> +	printf("dwMaxBitRate=%d\n", UGETDW(d->u.d.dwMaxBitRate));
>  	printf("dwMaxVideoFrameBufferSize=%d\n",
> -	    UGETDW(d->dwMaxVideoFrameBufferSize));
> +	    UGETDW(d->u.d.dwMaxVideoFrameBufferSize));
>  	printf("dwDefaultFrameInterval=%d\n",
> -	    UGETDW(d->dwDefaultFrameInterval));
> -	printf("bFrameIntervalType=0x%02x\n", d->bFrameIntervalType);
> +	    UGETDW(d->u.d.dwDefaultFrameInterval));
> +	printf("bFrameIntervalType=0x%02x\n", d->u.d.bFrameIntervalType);
>  
>  	p = (uint8_t *)d;
> -	p += sizeof(struct usb_video_frame_desc);
> +	p += UVIDEO_FRAME_MIN_LEN;
>  
> -	if (!d->bFrameIntervalType) {
> +	if (!d->u.d.bFrameIntervalType) {
>  		/* continuous */
> -		if (d->bLength < (sizeof(struct usb_video_frame_desc) +
> -		    sizeof(uDWord) * 3)) {
> +		if (d->bLength < UVIDEO_FRAME_MIN_LEN +
> +		    (sizeof(uDWord) * 3)) {
>  			printf("invalid frame descriptor length\n");
>  		} else {
>  			printf("dwMinFrameInterval = %d\n", UGETDW(p));
> @@ -3052,8 +3221,8 @@ uvideo_dump_desc_frame(struct uvideo_sof
>  		}
>  	} else {
>  		/* discrete */
> -		length = d->bLength - sizeof(struct usb_video_frame_desc);
> -		for (i = 0; i < d->bFrameIntervalType; i++) {
> +		length = d->bLength - UVIDEO_FRAME_MIN_LEN;
> +		for (i = 0; i < d->u.d.bFrameIntervalType; i++) {
>  			if (length <= 0) {
>  				printf("frame descriptor ended early\n");
>  				break;
> @@ -3088,6 +3257,108 @@ uvideo_dump_desc_format_uncompressed(str
>  }
>  
>  void
> +uvideo_dump_desc_format_h264(struct uvideo_softc *sc,
> +    const usb_descriptor_t *desc)
> +{
> +	struct usb_video_format_h264_desc *d;
> +
> +	d = (struct usb_video_format_h264_desc *)(uint8_t *)desc;
> +
> +	printf("bLength=%d\n", d->bLength);
> +	printf("bDescriptorType=0x%02x\n", d->bDescriptorType);
> +	printf("bDescriptorSubtype=0x%02x\n", d->bDescriptorSubtype);
> +	printf("bFormatIndex=0x%02x\n", d->bFormatIndex);
> +	printf("bNumFrameDescriptors=0x%02x\n", d->bNumFrameDescriptors);
> +	printf("bDefaultFrameIndex=0x%02x\n", d->bDefaultFrameIndex);
> +	printf("bMaxCodecConfigDelay=0x%02x\n", d->bMaxCodecConfigDelay);
> +	printf("bmSupportedSliceModes=0x%02x\n", d->bmSupportedSliceModes);
> +	printf("bmSupportedSyncFrameTypes=0x%02x\n",
> +	    d->bmSupportedSyncFrameTypes);
> +	printf("bmSupportedRateControlModes=0x%02x\n",
> +	    d->bmSupportedRateControlModes);
> +	printf("wMaxMBperSecOneResolutionNoScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecOneResolutionNoScalability));
> +	printf("wMaxMBperSecTwoResolutionsNoScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecTwoResolutionsNoScalability));
> +	printf("wMaxMBperSecOneResolutionTemporalQualityScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecOneResolutionTemporalQualityScalability));
> +	printf("wMaxMBperSecTwoResolutionsTemporalQualityScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecTwoResolutionsTemporalQualityScalability));
> +	printf("wMaxMBperSecThreeResolutionsTemporalQualityScalablity=%d\n",
> +	    UGETW(d->wMaxMBperSecThreeResolutionsTemporalQualityScalablity));
> +	printf("wMaxMBperSecFourResolutionsTemporalQualityScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecFourResolutionsTemporalQualityScalability));
> +	printf("wMaxMBperSecOneResolutionsTemporalSpatialScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecOneResolutionsTemporalSpatialScalability));
> +	printf("wMaxMBperSecTwoResolutionsTemporalSpatialScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecTwoResolutionsTemporalSpatialScalability));
> +	printf("wMaxMBperSecThreeResolutionsTemporalSpatialScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecThreeResolutionsTemporalSpatialScalability));
> +	printf("wMaxMBperSecFourResolutionsTemporalSpatialScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecFourResolutionsTemporalSpatialScalability));
> +	printf("wMaxMBperSecOneResolutionFullScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecOneResolutionFullScalability));
> +	printf("wMaxMBperSecTwoResolutionsFullScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecTwoResolutionsFullScalability));
> +	printf("wMaxMBperSecThreeResolutionsFullScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecThreeResolutionsFullScalability));
> +	printf("wMaxMBperSecFourResolutionsFullScalability=%d\n",
> +	    UGETW(d->wMaxMBperSecFourResolutionsFullScalability));
> +}
> +
> +void
> +uvideo_dump_desc_h264_frame(struct uvideo_softc *sc,
> +    const usb_descriptor_t *desc)
> +{
> +	struct usb_video_frame_desc *d;
> +	uint8_t *p;
> +	int length, i;
> +
> +	d = (struct usb_video_frame_desc *)(uint8_t *)desc;
> +
> +	printf("bLength=%d\n", d->bLength);
> +	printf("bDescriptorType=0x%02x\n", d->bDescriptorType);
> +	printf("bDescriptorSubtype=0x%02x\n", d->bDescriptorSubtype);
> +	printf("bFrameIndex=0x%02x\n", d->bFrameIndex);
> +	printf("wWidth=%d\n", UGETW(d->u.h264.wWidth));
> +	printf("wHeight=%d\n", UGETW(d->u.h264.wHeight));
> +	printf("wSARwidth=%d\n", UGETW(d->u.h264.wSARwidth));
> +	printf("wSARheight=%d\n", UGETW(d->u.h264.wSARheight));
> +	printf("wProfile=0x%04x\n", UGETW(d->u.h264.wProfile));
> +	printf("bLevelIDC=0x%02x\n", d->u.h264.bLevelIDC);
> +	printf("wConstrainedToolset=0x%04d\n",
> +	    UGETW(d->u.h264.wConstrainedToolset));
> +	printf("bmSupportedUsages=0x%08x\n",
> +	    UGETDW(d->u.h264.bmSupportedUsages));
> +	printf("bmCapabilities=0x%04d\n",
> +	    UGETW(d->u.h264.bmCapabilities));
> +	printf("bmSVCCapabilities=0x%08x\n",
> +	    UGETDW(d->u.h264.bmSVCCapabilities));
> +	printf("bmMVCCapabilities=0x%08x\n",
> +	    UGETDW(d->u.h264.bmMVCCapabilities));
> +	printf("dwMinBitRate=%d\n", UGETDW(d->u.h264.dwMinBitRate));
> +	printf("dwMaxBitRate=%d\n", UGETDW(d->u.h264.dwMaxBitRate));
> +	printf("dwDefaultFrameInterval=%d\n",
> +	    UGETDW(d->u.h264.dwDefaultFrameInterval));
> +	printf("bNumFrameIntervals=0x%02x\n",
> +	    d->u.h264.bNumFrameIntervals);
> +
> +	p = (uint8_t *)d;
> +	p += UVIDEO_FRAME_H264_MIN_LEN;;
> +
> +	length = d->bLength - UVIDEO_FRAME_H264_MIN_LEN;
> +	for (i = 0; i < d->u.h264.bNumFrameIntervals; i++) {
> +		if (length <= 0) {
> +			printf("frame descriptor ended early\n");
> +			break;
> +		}
> +		printf("dwFrameInterval = %d\n", UGETDW(p));
> +		p += sizeof(uDWord);
> +		length -= sizeof(uDWord);
> +	}
> +}
> +
> +void
>  uvideo_dump_desc_processing(struct uvideo_softc *sc,
>      const usb_descriptor_t *desc)
>  {
> @@ -3198,6 +3469,14 @@ uvideo_enum_fmt(void *v, struct v4l2_fmt
>  		    sizeof(fmtdesc->description));
>  		bzero(fmtdesc->reserved, sizeof(fmtdesc->reserved));
>  		break;
> +	case UDESCSUB_VS_FORMAT_H264:
> +	case UDESCSUB_VS_FORMAT_H264_SIMULCAST:
> +		fmtdesc->flags = V4L2_FMT_FLAG_COMPRESSED;
> +		(void)strlcpy(fmtdesc->description, "H.264",
> +		    sizeof(fmtdesc->description));
> +		fmtdesc->pixelformat = V4L2_PIX_FMT_H264;
> +		bzero(fmtdesc->reserved, sizeof(fmtdesc->reserved));
> +		break;
>  	default:
>  		fmtdesc->flags = 0;
>  		(void)strlcpy(fmtdesc->description, "Unknown Format",
> @@ -3215,6 +3494,7 @@ uvideo_enum_fsizes(void *v, struct v4l2_
>  {
>  	struct uvideo_softc *sc = v;
>  	int idx, found = 0;
> +	struct usb_video_frame_desc *frame = NULL;
>  
>  	for (idx = 0; idx < sc->sc_fmtgrp_num; idx++) {
>  		if (sc->sc_fmtgrp[idx].pixelformat == fsizes->pixel_format) {
> @@ -3229,10 +3509,14 @@ uvideo_enum_fsizes(void *v, struct v4l2_
>  		return (EINVAL);
>  
>  	fsizes->type = V4L2_FRMSIZE_TYPE_DISCRETE;
> -	fsizes->discrete.width =
> -	    UGETW(sc->sc_fmtgrp[idx].frame[fsizes->index]->wWidth);
> -	fsizes->discrete.height =
> -	    UGETW(sc->sc_fmtgrp[idx].frame[fsizes->index]->wHeight);
> +	frame = sc->sc_fmtgrp[idx].frame[fsizes->index];
> +	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264) {
> +		fsizes->discrete.width = UGETW(frame->u.h264.wWidth);
> +		fsizes->discrete.height = UGETW(frame->u.h264.wHeight);
> +	} else {
> +		fsizes->discrete.width = UGETW(frame->u.d.wWidth);
> +		fsizes->discrete.height = UGETW(frame->u.d.wHeight);
> +	}
>  
>  	return (0);
>  }
> @@ -3245,6 +3529,7 @@ uvideo_enum_fivals(void *v, struct v4l2_
>  	struct uvideo_format_group *fmtgrp = NULL;
>  	struct usb_video_frame_desc *frame = NULL;
>  	uint8_t *p;
> +	uint32_t width, height;
>  
>  	for (idx = 0; idx < sc->sc_fmtgrp_num; idx++) {
>  		if (sc->sc_fmtgrp[idx].pixelformat == fivals->pixel_format) {
> @@ -3256,8 +3541,19 @@ uvideo_enum_fivals(void *v, struct v4l2_
>  		return (EINVAL);
>  
>  	for (idx = 0; idx < fmtgrp->frame_num; idx++) {
> -		if (UGETW(fmtgrp->frame[idx]->wWidth) == fivals->width &&
> -		    UGETW(fmtgrp->frame[idx]->wHeight) == fivals->height) {
> +		switch (fmtgrp->frame[idx]->bDescriptorSubtype) {
> +		case UDESCSUB_VS_FRAME_H264:
> +			width = UGETW(fmtgrp->frame[idx]->u.h264.wWidth);
> +			height = UGETW(fmtgrp->frame[idx]->u.h264.wHeight);
> +			break;
> +
> +		default:
> +			width = UGETW(fmtgrp->frame[idx]->u.d.wWidth);
> +			height = UGETW(fmtgrp->frame[idx]->u.d.wHeight);
> +			break;
> +		}
> +
> +		if (width == fivals->width && height == fivals->height) {
>  			frame = fmtgrp->frame[idx];
>  			break;
>  		}
> @@ -3267,9 +3563,13 @@ uvideo_enum_fivals(void *v, struct v4l2_
>  
>  	/* byte-wise pointer to start of frame intervals */
>  	p = (uint8_t *)frame;
> -	p += sizeof(struct usb_video_frame_desc);
> +	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264)
> +		p += UVIDEO_FRAME_H264_MIN_LEN;
> +	else
> +		p += UVIDEO_FRAME_MIN_LEN;
>  
> -	if (frame->bFrameIntervalType == 0) {
> +	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264 ||
> +	    frame->u.d.bFrameIntervalType == 0) {
>  		if (fivals->index != 0)
>  			return (EINVAL);
>  		fivals->type = V4L2_FRMIVAL_TYPE_STEPWISE;
> @@ -3283,7 +3583,7 @@ uvideo_enum_fivals(void *v, struct v4l2_
>  		fivals->stepwise.step.denominator = 10000000;
>  		p += sizeof(uDWord);
>  	} else {
> -		if (fivals->index >= frame->bFrameIntervalType)
> +		if (fivals->index >= frame->u.d.bFrameIntervalType)
>  			return (EINVAL);
>  		p += sizeof(uDWord) * fivals->index;
>  		if (p > frame->bLength + (uint8_t *)frame) {
> @@ -3370,13 +3670,22 @@ int
>  uvideo_g_fmt(void *v, struct v4l2_format *fmt)
>  {
>  	struct uvideo_softc *sc = v;
> +	struct usb_video_frame_desc *frame;
>  
>  	if (fmt->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>  		return (EINVAL);
>  
>  	fmt->fmt.pix.pixelformat = sc->sc_fmtgrp_cur->pixelformat;
> -	fmt->fmt.pix.width = UGETW(sc->sc_fmtgrp_cur->frame_cur->wWidth);
> -	fmt->fmt.pix.height = UGETW(sc->sc_fmtgrp_cur->frame_cur->wHeight);
> +
> +	frame = sc->sc_fmtgrp_cur->frame_cur;
> +	if (frame->bDescriptorSubtype == UDESCSUB_VS_FRAME_H264) {
> +		fmt->fmt.pix.width = UGETW(frame->u.h264.wWidth);
> +		fmt->fmt.pix.height = UGETW(frame->u.h264.wHeight);
> +	} else {
> +		fmt->fmt.pix.width = UGETW(frame->u.d.wWidth);
> +		fmt->fmt.pix.height = UGETW(frame->u.d.wHeight);
> +	}
> +
>  	fmt->fmt.pix.sizeimage = UGETDW(sc->sc_desc_probe.dwMaxVideoFrameSize);
>  
>  	if (sc->sc_fmtgrp_cur->has_colorformat) {
> Index: sys/dev/usb/uvideo.h
> ===================================================================
> RCS file: /home/cvs/src/sys/dev/usb/uvideo.h,v
> diff -u -p -r1.65 uvideo.h
> --- sys/dev/usb/uvideo.h	19 Apr 2025 19:35:32 -0000	1.65
> +++ sys/dev/usb/uvideo.h	2 Aug 2025 11:08:37 -0000
> @@ -53,6 +53,9 @@
>  #define UDESCSUB_VS_FORMAT_FRAME_BASED			0x10
>  #define UDESCSUB_VS_FRAME_FRAME_BASED			0x11
>  #define UDESCSUB_VS_FORMAT_STREAM_BASED			0x12
> +#define UDESCSUB_VS_FORMAT_H264				0x13
> +#define UDESCSUB_VS_FRAME_H264				0x14
> +#define UDESCSUB_VS_FORMAT_H264_SIMULCAST		0x15
>  
>  /* Table A-8: Video Class-Specific Request Codes */
>  #define RC_UNDEFINED					0x00
> @@ -437,20 +440,53 @@ struct usb_video_format_mjpeg_desc {
>  	uByte	bCopyProtect;
>  } __packed;
>  
> -/* Table 3-2: Video Frame Descriptor (same for mjpeg and uncompressed)*/
>  struct usb_video_frame_desc {
>  	uByte	bLength;
>  	uByte	bDescriptorType;
>  	uByte	bDescriptorSubtype;
>  	uByte	bFrameIndex;
> -	uByte	bmCapabilities;
> -	uWord	wWidth;
> -	uWord	wHeight;
> -	uDWord	dwMinBitRate;
> -	uDWord	dwMaxBitRate;
> -	uDWord	dwMaxVideoFrameBufferSize;
> -	uDWord	dwDefaultFrameInterval;
> -	uByte	bFrameIntervalType;
> +	union {
> +	    /*
> +	     * Table 3-2: Video Frame Descriptor
> +	     * (same for mjpeg and uncompressed)
> +	     */
> +	    struct {
> +		uByte	bmCapabilities;
> +		uWord	wWidth;
> +		uWord	wHeight;
> +		uDWord	dwMinBitRate;
> +		uDWord	dwMaxBitRate;
> +		uDWord	dwMaxVideoFrameBufferSize;
> +		uDWord	dwDefaultFrameInterval;
> +		uByte	bFrameIntervalType;
> +	    } d;
> +#define UVIDEO_FRAME_MIN_LEN						\
> +	(offsetof(struct usb_video_frame_desc, u.d)			\
> +		+ sizeof(((struct usb_video_frame_desc *)0)->u.d))
> +
> +	    /* Table 3-2: H.264 Payload Video Frame Descriptor */
> +	    struct {
> +		uWord	wWidth;
> +		uWord	wHeight;
> +		uWord	wSARwidth;
> +		uWord	wSARheight;
> +		uWord	wProfile;
> +		uByte	bLevelIDC;
> +		uWord	wConstrainedToolset;
> +		uDWord	bmSupportedUsages;
> +		uWord	bmCapabilities;
> +		uDWord	bmSVCCapabilities;
> +		uDWord	bmMVCCapabilities;
> +		uDWord	dwMinBitRate;
> +		uDWord	dwMaxBitRate;
> +		uDWord	dwDefaultFrameInterval;
> +		uByte	bNumFrameIntervals;
> +	    } h264;
> +#define UVIDEO_FRAME_H264_MIN_LEN					\
> +	(offsetof(struct usb_video_frame_desc, u.h264)			\
> +		+ sizeof(((struct usb_video_frame_desc *)0)->u.h264))
> +
> +	} u;
>  	/* uDWord ivals[]; frame intervals, length varies */
>  } __packed;
>  
> @@ -473,6 +509,36 @@ struct usb_video_format_uncompressed_des
>  	uByte	bCopyProtect;
>  } __packed;
>  
> +/* Table 3-1: H.264 Payload Video Format Descriptor */
> +struct usb_video_format_h264_desc {
> +	uByte	bLength;
> +	uByte	bDescriptorType;
> +	uByte	bDescriptorSubtype;
> +	uByte	bFormatIndex;
> +	uByte	bNumFrameDescriptors;
> +	uByte	bDefaultFrameIndex;
> +	uByte	bMaxCodecConfigDelay;
> +	uByte	bmSupportedSliceModes;
> +	uByte	bmSupportedSyncFrameTypes;
> +	uByte	bResolutionScaling;
> +	uByte	_reserved1;
> +	uByte	bmSupportedRateControlModes;
> +	uWord	wMaxMBperSecOneResolutionNoScalability;
> +	uWord	wMaxMBperSecTwoResolutionsNoScalability;
> +	uWord	wMaxMBperSecOneResolutionTemporalQualityScalability;
> +	uWord	wMaxMBperSecTwoResolutionsTemporalQualityScalability;
> +	uWord	wMaxMBperSecThreeResolutionsTemporalQualityScalablity;
> +	uWord	wMaxMBperSecFourResolutionsTemporalQualityScalability;
> +	uWord	wMaxMBperSecOneResolutionsTemporalSpatialScalability;
> +	uWord	wMaxMBperSecTwoResolutionsTemporalSpatialScalability;
> +	uWord	wMaxMBperSecThreeResolutionsTemporalSpatialScalability;
> +	uWord	wMaxMBperSecFourResolutionsTemporalSpatialScalability;
> +	uWord	wMaxMBperSecOneResolutionFullScalability;
> +	uWord	wMaxMBperSecTwoResolutionsFullScalability;
> +	uWord	wMaxMBperSecThreeResolutionsFullScalability;
> +	uWord	wMaxMBperSecFourResolutionsFullScalability;
> +} __packed;
> +
>  /*
>   * Driver specific private definitions.
>   */
> @@ -503,6 +569,31 @@ struct uvideo_format_desc {
>  			uByte	bmInterlaceFlags;
>  			uByte	bCopyProtect;
>  		} uc;
> +
> +		/* h264 */
> +		struct {
> +			uByte	bDefaultFrameIndex;
> +			uByte	bMaxCodecConfigDelay;
> +			uByte	bmSupportedSliceModes;
> +			uByte	bmSupportedSyncFrameTypes;
> +			uByte	bResolutionScaling;
> +			uByte	_reserved1;
> +			uByte	bmSupportedRateControlModes;
> +			uDWord	wMaxMBperSecOneResolutionNoScalability;
> +			uDWord	wMaxMBperSecTwoResolutionsNoScalability;
> +			uDWord	wMaxMBperSecOneResolutionTemporalQualityScalability;
> +			uDWord	wMaxMBperSecTwoResolutionsTemporalQualityScalability;
> +			uDWord	wMaxMBperSecThreeResolutionsTemporalQualityScalablity;
> +			uDWord	wMaxMBperSecFourResolutionsTemporalQualityScalability;
> +			uDWord	wMaxMBperSecOneResolutionsTemporalSpatialScalability;
> +			uDWord	wMaxMBperSecTwoResolutionsTemporalSpatialScalability;
> +			uDWord	wMaxMBperSecThreeResolutionsTemporalSpatialScalability;
> +			uDWord	wMaxMBperSecFourResolutionsTemporalSpatialScalability;
> +			uDWord	wMaxMBperSecOneResolutionFullScalability;
> +			uDWord	wMaxMBperSecTwoResolutionsFullScalability;
> +			uDWord	wMaxMBperSecThreeResolutionsFullScalability;
> +			uDWord	wMaxMBperSecFourResolutionsFullScalability;
> +		} h264;
>  	} u;
>  } __packed;