Re: [RFC PATCH v6 08/11] media: uapi: define audio sample format fourcc type

From: Hans Verkuil
Date: Mon Oct 16 2023 - 08:32:37 EST


On 13/10/2023 10:31, Shengjiu Wang wrote:
> The audio sample format definition is from alsa,
> the header file is include/uapi/sound/asound.h, but
> don't include this header file directly, because in
> user space, there is another copy in alsa-lib.
> There will be conflict in userspace for include
> videodev2.h & asound.h and asoundlib.h
>
> Here still use the fourcc format.
>
> Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx>
> ---
> .../userspace-api/media/v4l/pixfmt-audio.rst | 202 ++++++++++++++++++
> .../userspace-api/media/v4l/pixfmt.rst | 1 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 36 ++++
> include/uapi/linux/videodev2.h | 48 +++++
> 4 files changed, 287 insertions(+)
> create mode 100644 Documentation/userspace-api/media/v4l/pixfmt-audio.rst
>
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-audio.rst b/Documentation/userspace-api/media/v4l/pixfmt-audio.rst
> new file mode 100644
> index 000000000000..ac89b2c4b594
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-audio.rst
> @@ -0,0 +1,202 @@
> +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
> +
> +.. _pixfmt-audio:
> +
> +*************
> +Audio Formats
> +*************
> +
> +These formats are used for :ref:`audiomem2mem` interface only.
> +
> +.. tabularcolumns:: |p{5.8cm}|p{1.2cm}|p{10.3cm}|
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: Audio Format
> + :header-rows: 1
> + :stub-columns: 0
> + :widths: 3 1 4
> +
> + * - Identifier
> + - Code
> + - Details
> + * .. _V4L2-AUDIO-FMT-S8:
> +
> + - ``V4L2_AUDIO_FMT_S8``
> + - 'S8'
> + - Corresponds to SNDRV_PCM_FORMAT_S8 in ALSA
> + * .. _V4L2-AUDIO-FMT-U8:
> +
> + - ``V4L2_AUDIO_FMT_U8``
> + - 'U8'
> + - Corresponds to SNDRV_PCM_FORMAT_U8 in ALSA
> + * .. _V4L2-AUDIO-FMT-S16-LE:
> +
> + - ``V4L2_AUDIO_FMT_S16_LE``
> + - 'S16_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S16_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S16-BE:
> +
> + - ``V4L2_AUDIO_FMT_S16_BE``
> + - 'S16_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S16_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U16-LE:
> +
> + - ``V4L2_AUDIO_FMT_U16_LE``
> + - 'U16_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U16_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U16-BE:
> +
> + - ``V4L2_AUDIO_FMT_U16_BE``
> + - 'U16_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U16_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S24-LE:
> +
> + - ``V4L2_AUDIO_FMT_S24_LE``
> + - 'S24_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S24_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S24-BE:
> +
> + - ``V4L2_AUDIO_FMT_S24_BE``
> + - 'S24_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S24_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U24-LE:
> +
> + - ``V4L2_AUDIO_FMT_U24_LE``
> + - 'U24_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U24_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U24-BE:
> +
> + - ``V4L2_AUDIO_FMT_U24_BE``
> + - 'U24_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U24_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S32-LE:
> +
> + - ``V4L2_AUDIO_FMT_S32_LE``
> + - 'S32_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S32_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S32-BE:
> +
> + - ``V4L2_AUDIO_FMT_S32_BE``
> + - 'S32_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S32_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U32-LE:
> +
> + - ``V4L2_AUDIO_FMT_U32_LE``
> + - 'U32_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U32_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U32-BE:
> +
> + - ``V4L2_AUDIO_FMT_U32_BE``
> + - 'U32_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U32_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-FLOAT-LE:
> +
> + - ``V4L2_AUDIO_FMT_FLOAT_LE``
> + - 'FLOAT_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_FLOAT_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-FLOAT-BE:
> +
> + - ``V4L2_AUDIO_FMT_FLOAT_BE``
> + - 'FLOAT_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_FLOAT_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-FLOAT64-LE:
> +
> + - ``V4L2_AUDIO_FMT_FLOAT64_LE``
> + - 'FLOAT64_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_FLOAT64_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-FLOAT64-BE:
> +
> + - ``V4L2_AUDIO_FMT_FLOAT64_BE``
> + - 'FLOAT64_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_FLOAT64_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-IEC958-SUBFRAME-LE:
> +
> + - ``V4L2_AUDIO_FMT_IEC958_SUBFRAME_LE``
> + - 'IEC958_SUBFRAME_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-IEC958-SUBFRAME-BE:
> +
> + - ``V4L2_AUDIO_FMT_IEC958_SUBFRAME_BE``
> + - 'IEC958_SUBFRAME_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S20-LE:
> +
> + - ``V4L2_AUDIO_FMT_S20_LE``
> + - 'S20_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S20_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S20-BE:
> +
> + - ``V4L2_AUDIO_FMT_S20_BE``
> + - 'S20_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S20_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U20-LE:
> +
> + - ``V4L2_AUDIO_FMT_U20_LE``
> + - 'U20_LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U20_LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U20-BE:
> +
> + - ``V4L2_AUDIO_FMT_U20_BE``
> + - 'U20_BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U20_BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S24-3LE:
> +
> + - ``V4L2_AUDIO_FMT_S24_3LE``
> + - 'S24_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S24_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S24-3BE:
> +
> + - ``V4L2_AUDIO_FMT_S24_3BE``
> + - 'S24_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S24_3BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U24-3LE:
> +
> + - ``V4L2_AUDIO_FMT_U24_3LE``
> + - 'U24_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U24_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U24-3BE:
> +
> + - ``V4L2_AUDIO_FMT_U24_3BE``
> + - 'U24_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U24_3BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S20-3LE:
> +
> + - ``V4L2_AUDIO_FMT_S20_3LE``
> + - 'S20_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S24_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S20-3BE:
> +
> + - ``V4L2_AUDIO_FMT_S20_3BE``
> + - 'S20_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S20_3BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U20-3LE:
> +
> + - ``V4L2_AUDIO_FMT_U20_3LE``
> + - 'U20_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U20_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U20-3BE:
> +
> + - ``V4L2_AUDIO_FMT_U20_3BE``
> + - 'U20_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U20_3BE in ALSA
> + * .. _V4L2-AUDIO-FMT-S18-3LE:
> +
> + - ``V4L2_AUDIO_FMT_S18_3LE``
> + - 'S18_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_S18_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-S18-3BE:
> +
> + - ``V4L2_AUDIO_FMT_S18_3BE``
> + - 'S18_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_S18_3BE in ALSA
> + * .. _V4L2-AUDIO-FMT-U18-3LE:
> +
> + - ``V4L2_AUDIO_FMT_U18_3LE``
> + - 'U18_3LE'
> + - Corresponds to SNDRV_PCM_FORMAT_U18_3LE in ALSA
> + * .. _V4L2-AUDIO-FMT-U18-3BE:
> +
> + - ``V4L2_AUDIO_FMT_U18_3BE``
> + - 'U18_3BE'
> + - Corresponds to SNDRV_PCM_FORMAT_U18_3BE in ALSA
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt.rst b/Documentation/userspace-api/media/v4l/pixfmt.rst
> index 11dab4a90630..2eb6fdd3b43d 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt.rst
> @@ -36,3 +36,4 @@ see also :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>`.)
> colorspaces
> colorspaces-defs
> colorspaces-details
> + pixfmt-audio
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 5d088e6c43e4..31e443c644db 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1471,6 +1471,42 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_PIX_FMT_Y210: descr = "10-bit YUYV Packed"; break;
> case V4L2_PIX_FMT_Y212: descr = "12-bit YUYV Packed"; break;
> case V4L2_PIX_FMT_Y216: descr = "16-bit YUYV Packed"; break;
> + case V4L2_AUDIO_FMT_S8: descr = "8-bit Signed"; break;
> + case V4L2_AUDIO_FMT_U8: descr = "8-bit Unsigned"; break;
> + case V4L2_AUDIO_FMT_S16_LE: descr = "16-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S16_BE: descr = "16-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U16_LE: descr = "16-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U16_BE: descr = "16-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_S24_LE: descr = "24(32)-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S24_BE: descr = "24(32)-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U24_LE: descr = "24(32)-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U24_BE: descr = "24(32)-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_S32_LE: descr = "32-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S32_BE: descr = "32-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U32_LE: descr = "32-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U32_BE: descr = "32-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_FLOAT_LE: descr = "32-bit Float LE"; break;
> + case V4L2_AUDIO_FMT_FLOAT_BE: descr = "32-bit Float BE"; break;
> + case V4L2_AUDIO_FMT_FLOAT64_LE: descr = "64-bit Float LE"; break;
> + case V4L2_AUDIO_FMT_FLOAT64_BE: descr = "64-bit Float BE"; break;
> + case V4L2_AUDIO_FMT_IEC958_SUBFRAME_LE: descr = "32-bit IEC958 LE"; break;
> + case V4L2_AUDIO_FMT_IEC958_SUBFRAME_BE: descr = "32-bit IEC958 BE"; break;
> + case V4L2_AUDIO_FMT_S20_LE: descr = "20-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S20_BE: descr = "20-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U20_LE: descr = "20-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U20_BE: descr = "20-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_S24_3LE: descr = "24(24)-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S24_3BE: descr = "24(24)-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U24_3LE: descr = "24(24)-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U24_3BE: descr = "24(24)-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_S20_3LE: descr = "20(24)-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S20_3BE: descr = "20(24)-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U20_3LE: descr = "20(24)-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U20_3BE: descr = "20(24)-bit Unsigned BE"; break;
> + case V4L2_AUDIO_FMT_S18_3LE: descr = "18(24)-bit Signed LE"; break;
> + case V4L2_AUDIO_FMT_S18_3BE: descr = "18(24)-bit Signed BE"; break;
> + case V4L2_AUDIO_FMT_U18_3LE: descr = "18(24)-bit Unsigned LE"; break;
> + case V4L2_AUDIO_FMT_U18_3BE: descr = "18(24)-bit Unsigned BE"; break;

This still has several formats that are not used by the initial drivers imx-asrc
and viaudm2m. Please just add the ones that are actually used.

We had bad experiences in the past with defined-but-never-used formats, so we
are fairly strict about that these days.

>
> default:
> /* Compressed formats */
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index b0ddb7319d36..2ac7b989394c 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -842,6 +842,54 @@ struct v4l2_pix_format {
> #define V4L2_META_FMT_RK_ISP1_PARAMS v4l2_fourcc('R', 'K', '1', 'P') /* Rockchip ISP1 3A Parameters */
> #define V4L2_META_FMT_RK_ISP1_STAT_3A v4l2_fourcc('R', 'K', '1', 'S') /* Rockchip ISP1 3A Statistics */
>
> +/*
> + * Audio-data formats
> + * All these audio formats use a fourcc starting with 'AU'
> + * followed by the SNDRV_PCM_FORMAT_ value from asound.h.
> + */
> +#define V4L2_AUDIO_FMT_S8 v4l2_fourcc('A', 'U', '0', '0')
> +#define V4L2_AUDIO_FMT_U8 v4l2_fourcc('A', 'U', '0', '1')
> +#define V4L2_AUDIO_FMT_S16_LE v4l2_fourcc('A', 'U', '0', '2')
> +#define V4L2_AUDIO_FMT_S16_BE v4l2_fourcc('A', 'U', '0', '3')
> +#define V4L2_AUDIO_FMT_U16_LE v4l2_fourcc('A', 'U', '0', '4')
> +#define V4L2_AUDIO_FMT_U16_BE v4l2_fourcc('A', 'U', '0', '5')
> +#define V4L2_AUDIO_FMT_S24_LE v4l2_fourcc('A', 'U', '0', '6')
> +#define V4L2_AUDIO_FMT_S24_BE v4l2_fourcc('A', 'U', '0', '7')
> +#define V4L2_AUDIO_FMT_U24_LE v4l2_fourcc('A', 'U', '0', '8')
> +#define V4L2_AUDIO_FMT_U24_BE v4l2_fourcc('A', 'U', '0', '9')
> +
> +#define V4L2_AUDIO_FMT_S32_LE v4l2_fourcc('A', 'U', '1', '0')
> +#define V4L2_AUDIO_FMT_S32_BE v4l2_fourcc('A', 'U', '1', '1')
> +#define V4L2_AUDIO_FMT_U32_LE v4l2_fourcc('A', 'U', '1', '2')
> +#define V4L2_AUDIO_FMT_U32_BE v4l2_fourcc('A', 'U', '1', '3')
> +#define V4L2_AUDIO_FMT_FLOAT_LE v4l2_fourcc('A', 'U', '1', '4')
> +#define V4L2_AUDIO_FMT_FLOAT_BE v4l2_fourcc('A', 'U', '1', '5')
> +#define V4L2_AUDIO_FMT_FLOAT64_LE v4l2_fourcc('A', 'U', '1', '6')
> +#define V4L2_AUDIO_FMT_FLOAT64_BE v4l2_fourcc('A', 'U', '1', '7')
> +#define V4L2_AUDIO_FMT_IEC958_SUBFRAME_LE v4l2_fourcc('A', 'U', '1', '8')
> +#define V4L2_AUDIO_FMT_IEC958_SUBFRAME_BE v4l2_fourcc('A', 'U', '1', '9')
> +
> +#define V4L2_AUDIO_FMT_S20_LE v4l2_fourcc('A', 'U', '2', '5')
> +#define V4L2_AUDIO_FMT_S20_BE v4l2_fourcc('A', 'U', '2', '6')
> +#define V4L2_AUDIO_FMT_U20_LE v4l2_fourcc('A', 'U', '2', '7')
> +#define V4L2_AUDIO_FMT_U20_BE v4l2_fourcc('A', 'U', '2', '8')
> +
> +#define V4L2_AUDIO_FMT_S24_3LE v4l2_fourcc('A', 'U', '3', '2')
> +#define V4L2_AUDIO_FMT_S24_3BE v4l2_fourcc('A', 'U', '3', '3')
> +#define V4L2_AUDIO_FMT_U24_3LE v4l2_fourcc('A', 'U', '3', '4')
> +#define V4L2_AUDIO_FMT_U24_3BE v4l2_fourcc('A', 'U', '3', '5')
> +#define V4L2_AUDIO_FMT_S20_3LE v4l2_fourcc('A', 'U', '3', '6')
> +#define V4L2_AUDIO_FMT_S20_3BE v4l2_fourcc('A', 'U', '3', '7')
> +#define V4L2_AUDIO_FMT_U20_3LE v4l2_fourcc('A', 'U', '3', '8')
> +#define V4L2_AUDIO_FMT_U20_3BE v4l2_fourcc('A', 'U', '3', '9')
> +#define V4L2_AUDIO_FMT_S18_3LE v4l2_fourcc('A', 'U', '4', '0')
> +#define V4L2_AUDIO_FMT_S18_3BE v4l2_fourcc('A', 'U', '4', '1')
> +#define V4L2_AUDIO_FMT_U18_3LE v4l2_fourcc('A', 'U', '4', '2')
> +#define V4L2_AUDIO_FMT_U18_3BE v4l2_fourcc('A', 'U', '4', '3')
> +
> +#define v4l2_fourcc_to_audfmt(X) \
> + (((((X) >> 16) & 0xFF) - '0') * 10 + ((((X) >> 24) & 0xFF) - '0'))

X -> fourcc
0xFF -> 0xff

> +
> /* priv field value to indicates that subsequent fields are valid. */
> #define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe
>

Regards,

Hans