new file mode 100644
@@ -0,0 +1,15 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _audio-formats:
+
+*************
+Audio Formats
+*************
+
+These formats are used for :ref:`audio` interface only.
+
+
+.. toctree::
+ :maxdepth: 1
+
+ pixfmt-aud-lpcm
new file mode 100644
@@ -0,0 +1,61 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _v4l2-audio-fmt-lpcm:
+
+****************************
+V4L2_AUDIO_FMT_LPCM ('LPCM')
+****************************
+
+Linear Pulse-Code Modulation (LPCM)
+
+
+Description
+===========
+
+LPCM audio is coded using a combination of values such as:
+
+Sample rate: which is the number of times per second that samples are taken,
+The typical rates are 8kHz, 11025Hz, 16kHz, 22050Hz, 32kHz, 44100Hz, 48kHz,
+88200Hz, 96kHz, 176400Hz, 192kHz...
+
+Sample format: which determines the number of possible digital values that
+can be used to represent each sample. The format can be SND_PCM_FORMAT_S8,
+SND_PCM_FORMAT_S16_LE, SND_PCM_FORMAT_S24_LE, SND_PCM_FORMAT_S32_LE...
+
+Channels: It is the "location" or "passageway" of a specific signal or
+data in a piece of audio. The channel number can be 1,2,3...
+
+Please refer to https://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html
+for more detail
+
+Each sample contains several channels data, the channel data format is
+defined by sample format.
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+
+ * - Sample 0:
+ - Channel 0
+ - Channel 1
+ - Channel 2
+ - Channel 3
+ - ...
+ * - Sample 1:
+ - Channel 0
+ - Channel 1
+ - Channel 2
+ - Channel 3
+ - ...
+ * - Sample 2:
+ - Channel 0
+ - Channel 1
+ - Channel 2
+ - Channel 3
+ - ...
+ * - Sample 3:
+ - Channel 0
+ - Channel 1
+ - Channel 2
+ - Channel 3
+ - ...
@@ -36,3 +36,4 @@ see also :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>`.)
colorspaces
colorspaces-defs
colorspaces-details
+ audio-formats
@@ -1452,6 +1452,7 @@ 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_LPCM: descr = "Audio LPCM"; break;
default:
/* Compressed formats */
@@ -839,6 +839,9 @@ 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 */
+#define V4L2_AUDIO_FMT_LPCM v4l2_fourcc('L', 'P', 'C', 'M') /* audio lpcm */
+
/* priv field value to indicates that subsequent fields are valid. */
#define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe
Linear Pulse-Code Modulation is used to represent audio samples in buffer, the samples for each channel are interleaved. Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> --- .../userspace-api/media/v4l/audio-formats.rst | 15 +++++ .../media/v4l/pixfmt-aud-lpcm.rst | 61 +++++++++++++++++++ .../userspace-api/media/v4l/pixfmt.rst | 1 + drivers/media/v4l2-core/v4l2-ioctl.c | 1 + include/uapi/linux/videodev2.h | 3 + 5 files changed, 81 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/audio-formats.rst create mode 100644 Documentation/userspace-api/media/v4l/pixfmt-aud-lpcm.rst