gstreamer/gst-libs/gst/vaapi/gstvaapiencoder_vp8.c
Hyunjun Ko b6a3e88059 libs: encoder: vp8: add CBR encoding mode
This patch enables the Constant BitRate encoding mode in VP8 encoder.
Basically it adds the configuration parameters required by libva to
CBR enconding.

Original-Patch-By: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>

https://bugzilla.gnome.org/show_bug.cgi?id=749950
2017-02-10 13:11:21 +01:00

643 lines
19 KiB
C

/*
* gstvaapiencoder_vp8.c - VP8 encoder
*
* Copyright (C) 2015 Intel Corporation
* Author: Sreerenj Balachandran <sreerenj.balachandran@intel.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
#include "sysdeps.h"
#include <va/va.h>
#include <va/va_enc_vp8.h>
#include <gst/base/gstbitwriter.h>
#include <gst/codecparsers/gstvp8parser.h>
#include "gstvaapicompat.h"
#include "gstvaapiencoder_priv.h"
#include "gstvaapiencoder_vp8.h"
#include "gstvaapicodedbufferproxy_priv.h"
#include "gstvaapisurface.h"
#define DEBUG 1
#include "gstvaapidebug.h"
/* Define default rate control mode ("constant-qp") */
#define DEFAULT_RATECONTROL GST_VAAPI_RATECONTROL_CQP
/* Supported set of VA rate controls, within this implementation */
#define SUPPORTED_RATECONTROLS \
(GST_VAAPI_RATECONTROL_MASK (CQP) | \
GST_VAAPI_RATECONTROL_MASK (CBR))
/* Supported set of tuning options, within this implementation */
#define SUPPORTED_TUNE_OPTIONS \
(GST_VAAPI_ENCODER_TUNE_MASK (NONE))
/* Supported set of VA packed headers, within this implementation */
#define SUPPORTED_PACKED_HEADERS \
(VA_ENC_PACKED_HEADER_NONE)
#define DEFAULT_LOOP_FILTER_LEVEL 0
#define DEFAULT_SHARPNESS_LEVEL 0
#define DEFAULT_YAC_QI 40
/* ------------------------------------------------------------------------- */
/* --- VP8 Encoder --- */
/* ------------------------------------------------------------------------- */
#define GST_VAAPI_ENCODER_VP8_CAST(encoder) \
((GstVaapiEncoderVP8 *)(encoder))
struct _GstVaapiEncoderVP8
{
GstVaapiEncoder parent_instance;
GstVaapiProfile profile;
guint loop_filter_level;
guint sharpness_level;
guint yac_qi;
guint frame_num;
/* reference list */
GstVaapiSurfaceProxy *last_ref;
GstVaapiSurfaceProxy *golden_ref;
GstVaapiSurfaceProxy *alt_ref;
};
/* Derives the profile that suits best to the configuration */
static GstVaapiEncoderStatus
ensure_profile (GstVaapiEncoderVP8 * encoder)
{
/* Always start from "simple" profile for maximum compatibility */
encoder->profile = GST_VAAPI_PROFILE_VP8;
return GST_VAAPI_ENCODER_STATUS_SUCCESS;
}
/* Derives the profile supported by the underlying hardware */
static gboolean
ensure_hw_profile (GstVaapiEncoderVP8 * encoder)
{
GstVaapiDisplay *const display = GST_VAAPI_ENCODER_DISPLAY (encoder);
GstVaapiEntrypoint entrypoint = GST_VAAPI_ENTRYPOINT_SLICE_ENCODE;
GstVaapiProfile profile, profiles[2];
guint i, num_profiles = 0;
profiles[num_profiles++] = encoder->profile;
profile = GST_VAAPI_PROFILE_UNKNOWN;
for (i = 0; i < num_profiles; i++) {
if (gst_vaapi_display_has_encoder (display, profiles[i], entrypoint)) {
profile = profiles[i];
break;
}
}
if (profile == GST_VAAPI_PROFILE_UNKNOWN)
goto error_unsupported_profile;
GST_VAAPI_ENCODER_CAST (encoder)->profile = profile;
return TRUE;
/* ERRORS */
error_unsupported_profile:
{
GST_ERROR ("unsupported HW profile (0x%08x)", encoder->profile);
return FALSE;
}
}
static gboolean
ensure_bitrate (GstVaapiEncoderVP8 * encoder)
{
GstVaapiEncoder *const base_encoder = GST_VAAPI_ENCODER_CAST (encoder);
/* Default compression: 64 bits per macroblock */
switch (GST_VAAPI_ENCODER_RATE_CONTROL (encoder)) {
case GST_VAAPI_RATECONTROL_CBR:
if (!base_encoder->bitrate) {
base_encoder->bitrate =
gst_util_uint64_scale (GST_VAAPI_ENCODER_WIDTH (encoder) *
GST_VAAPI_ENCODER_HEIGHT (encoder),
GST_VAAPI_ENCODER_FPS_N (encoder),
GST_VAAPI_ENCODER_FPS_D (encoder)) / (4 * 1000);
}
break;
default:
base_encoder->bitrate = 0;
break;
}
return TRUE;
}
static GstVaapiEncoderStatus
set_context_info (GstVaapiEncoder * base_encoder)
{
GstVaapiEncoderVP8 *encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
GstVideoInfo *const vip = GST_VAAPI_ENCODER_VIDEO_INFO (encoder);
/* Maximum sizes for common headers (in bytes) */
enum
{
MAX_FRAME_TAG_SIZE = 10,
MAX_UPDATE_SEGMENTATION_SIZE = 13,
MAX_MB_LF_ADJUSTMENTS_SIZE = 9,
MAX_QUANT_INDICES_SIZE = 5,
MAX_TOKEN_PROB_UPDATE_SIZE = 1188,
MAX_MV_PROBE_UPDATE_SIZE = 38,
MAX_REST_OF_FRAME_HDR_SIZE = 15
};
if (!ensure_hw_profile (encoder))
return GST_VAAPI_ENCODER_STATUS_ERROR_UNSUPPORTED_PROFILE;
base_encoder->num_ref_frames = 3;
/* Only YUV 4:2:0 formats are supported for now. */
/* Assumig 4 times compression ratio */
base_encoder->codedbuf_size = GST_ROUND_UP_16 (vip->width) *
GST_ROUND_UP_16 (vip->height) * 12 / 4;
base_encoder->codedbuf_size +=
MAX_FRAME_TAG_SIZE + MAX_UPDATE_SEGMENTATION_SIZE +
MAX_MB_LF_ADJUSTMENTS_SIZE + MAX_QUANT_INDICES_SIZE +
MAX_TOKEN_PROB_UPDATE_SIZE + MAX_MV_PROBE_UPDATE_SIZE +
MAX_REST_OF_FRAME_HDR_SIZE;
return GST_VAAPI_ENCODER_STATUS_SUCCESS;
}
static void
clear_ref (GstVaapiEncoderVP8 * encoder, GstVaapiSurfaceProxy ** ref)
{
if (*ref) {
gst_vaapi_encoder_release_surface (GST_VAAPI_ENCODER (encoder), *ref);
*ref = NULL;
}
}
static void
clear_references (GstVaapiEncoderVP8 * encoder)
{
clear_ref (encoder, &encoder->last_ref);
clear_ref (encoder, &encoder->golden_ref);
clear_ref (encoder, &encoder->alt_ref);
}
static void
push_reference (GstVaapiEncoderVP8 * encoder, GstVaapiSurfaceProxy * ref)
{
if (encoder->last_ref == NULL) {
encoder->golden_ref = gst_vaapi_surface_proxy_ref (ref);
encoder->alt_ref = gst_vaapi_surface_proxy_ref (ref);
} else {
clear_ref (encoder, &encoder->alt_ref);
encoder->alt_ref = encoder->golden_ref;
encoder->golden_ref = encoder->last_ref;
}
encoder->last_ref = ref;
}
static gboolean
fill_sequence (GstVaapiEncoderVP8 * encoder, GstVaapiEncSequence * sequence)
{
GstVaapiEncoder *const base_encoder = GST_VAAPI_ENCODER_CAST (encoder);
VAEncSequenceParameterBufferVP8 *const seq_param = sequence->param;
memset (seq_param, 0, sizeof (VAEncSequenceParameterBufferVP8));
seq_param->frame_width = GST_VAAPI_ENCODER_WIDTH (encoder);
seq_param->frame_height = GST_VAAPI_ENCODER_HEIGHT (encoder);
if (GST_VAAPI_ENCODER_RATE_CONTROL (encoder) & GST_VAAPI_RATECONTROL_CBR)
seq_param->bits_per_second = base_encoder->bitrate * 1000;
seq_param->intra_period = base_encoder->keyframe_period;
return TRUE;
}
static gboolean
ensure_sequence (GstVaapiEncoderVP8 * encoder, GstVaapiEncPicture * picture)
{
GstVaapiEncSequence *sequence;
g_assert (picture);
if (picture->type != GST_VAAPI_PICTURE_TYPE_I)
return TRUE;
sequence = GST_VAAPI_ENC_SEQUENCE_NEW (VP8, encoder);
if (!sequence)
goto error;
if (!fill_sequence (encoder, sequence))
goto error;
gst_vaapi_enc_picture_set_sequence (picture, sequence);
gst_vaapi_codec_object_replace (&sequence, NULL);
return TRUE;
/* ERRORS */
error:
{
gst_vaapi_codec_object_replace (&sequence, NULL);
return FALSE;
}
}
static gboolean
ensure_misc_params (GstVaapiEncoderVP8 * encoder, GstVaapiEncPicture * picture)
{
GstVaapiEncoder *const base_encoder = GST_VAAPI_ENCODER_CAST (encoder);
GstVaapiEncMiscParam *misc;
if (GST_VAAPI_ENCODER_RATE_CONTROL (encoder) != GST_VAAPI_RATECONTROL_CBR)
return TRUE;
misc = GST_VAAPI_ENC_MISC_PARAM_NEW (FrameRate, encoder);
if (!misc)
return FALSE;
{
VAEncMiscParameterFrameRate *param = misc->data;
param->framerate =
GST_VAAPI_ENCODER_FPS_N (encoder) / GST_VAAPI_ENCODER_FPS_D (encoder);
}
gst_vaapi_enc_picture_add_misc_param (picture, misc);
gst_vaapi_codec_object_replace (&misc, NULL);
misc = GST_VAAPI_ENC_MISC_PARAM_NEW (HRD, encoder);
if (!misc)
return FALSE;
{
VAEncMiscParameterHRD *hrd = misc->data;
if (base_encoder->bitrate > 0) {
hrd->buffer_size = base_encoder->bitrate * 1000 * 2;
hrd->initial_buffer_fullness = base_encoder->bitrate * 1000;
} else {
hrd->buffer_size = 0;
hrd->initial_buffer_fullness = 0;
}
}
gst_vaapi_enc_picture_add_misc_param (picture, misc);
gst_vaapi_codec_object_replace (&misc, NULL);
/* RateControl params */
misc = GST_VAAPI_ENC_MISC_PARAM_NEW (RateControl, encoder);
if (!misc)
return FALSE;
{
VAEncMiscParameterRateControl *rate_control;
rate_control = misc->data;
rate_control->bits_per_second = base_encoder->bitrate * 1000;
rate_control->target_percentage = 70;
/* CPB (Coded picture buffer) length in milliseconds, which could
* be provided as a property */
rate_control->window_size = 500;
rate_control->initial_qp = encoder->yac_qi;
rate_control->min_qp = 1;
}
gst_vaapi_enc_picture_add_misc_param (picture, misc);
gst_vaapi_codec_object_replace (&misc, NULL);
return TRUE;
}
static gboolean
fill_picture (GstVaapiEncoderVP8 * encoder,
GstVaapiEncPicture * picture,
GstVaapiCodedBuffer * codedbuf, GstVaapiSurfaceProxy * surface)
{
VAEncPictureParameterBufferVP8 *const pic_param = picture->param;
int i;
memset (pic_param, 0, sizeof (VAEncPictureParameterBufferVP8));
pic_param->reconstructed_frame = GST_VAAPI_SURFACE_PROXY_SURFACE_ID (surface);
pic_param->coded_buf = GST_VAAPI_OBJECT_ID (codedbuf);
if (picture->type == GST_VAAPI_PICTURE_TYPE_P) {
pic_param->pic_flags.bits.frame_type = 1;
pic_param->ref_arf_frame =
GST_VAAPI_SURFACE_PROXY_SURFACE_ID (encoder->alt_ref);
pic_param->ref_gf_frame =
GST_VAAPI_SURFACE_PROXY_SURFACE_ID (encoder->golden_ref);
pic_param->ref_last_frame =
GST_VAAPI_SURFACE_PROXY_SURFACE_ID (encoder->last_ref);
pic_param->pic_flags.bits.refresh_last = 1;
pic_param->pic_flags.bits.refresh_golden_frame = 0;
pic_param->pic_flags.bits.copy_buffer_to_golden = 1;
pic_param->pic_flags.bits.refresh_alternate_frame = 0;
pic_param->pic_flags.bits.copy_buffer_to_alternate = 2;
} else {
pic_param->ref_last_frame = VA_INVALID_SURFACE;
pic_param->ref_gf_frame = VA_INVALID_SURFACE;
pic_param->ref_arf_frame = VA_INVALID_SURFACE;
pic_param->pic_flags.bits.refresh_last = 1;
pic_param->pic_flags.bits.refresh_golden_frame = 1;
pic_param->pic_flags.bits.refresh_alternate_frame = 1;
}
pic_param->pic_flags.bits.show_frame = 1;
if (encoder->loop_filter_level) {
pic_param->pic_flags.bits.version = 1;
pic_param->pic_flags.bits.loop_filter_type = 1; /* Enable simple loop filter */
/* Disabled segmentation, so what matters is only loop_filter_level[0] */
for (i = 0; i < 4; i++)
pic_param->loop_filter_level[i] = encoder->loop_filter_level;
}
pic_param->sharpness_level = encoder->sharpness_level;
/* Used for CBR */
pic_param->clamp_qindex_low = 0;
pic_param->clamp_qindex_high = 127;
return TRUE;
}
static gboolean
ensure_picture (GstVaapiEncoderVP8 * encoder, GstVaapiEncPicture * picture,
GstVaapiCodedBufferProxy * codedbuf_proxy, GstVaapiSurfaceProxy * surface)
{
GstVaapiCodedBuffer *const codedbuf =
GST_VAAPI_CODED_BUFFER_PROXY_BUFFER (codedbuf_proxy);
if (!fill_picture (encoder, picture, codedbuf, surface))
return FALSE;
return TRUE;
}
static gboolean
fill_quantization_table (GstVaapiEncoderVP8 * encoder,
GstVaapiEncPicture * picture, GstVaapiEncQMatrix * q_matrix)
{
VAQMatrixBufferVP8 *const qmatrix_param = q_matrix->param;
int i;
memset (qmatrix_param, 0, sizeof (VAQMatrixBufferVP8));
/* DefaultYacQantVal = 8 for I frame, which is ac_qlookup[4] and
* DefaultYacQantVAl = 44 for P frame, which is ac_qllookup[40] */
for (i = 0; i < 4; i++) {
if (encoder->yac_qi == DEFAULT_YAC_QI) {
if (picture->type == GST_VAAPI_PICTURE_TYPE_I)
qmatrix_param->quantization_index[i] = 4;
else
qmatrix_param->quantization_index[i] = 40;
} else
qmatrix_param->quantization_index[i] = encoder->yac_qi;
}
return TRUE;
}
static gboolean
ensure_quantization_table (GstVaapiEncoderVP8 * encoder,
GstVaapiEncPicture * picture)
{
g_assert (picture);
picture->q_matrix = GST_VAAPI_ENC_Q_MATRIX_NEW (VP8, encoder);
if (!picture->q_matrix) {
GST_ERROR ("failed to allocate quantiser table");
return GST_VAAPI_DECODER_STATUS_ERROR_ALLOCATION_FAILED;
}
if (!fill_quantization_table (encoder, picture, picture->q_matrix))
return FALSE;
return TRUE;
}
static GstVaapiEncoderStatus
gst_vaapi_encoder_vp8_encode (GstVaapiEncoder * base_encoder,
GstVaapiEncPicture * picture, GstVaapiCodedBufferProxy * codedbuf)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
GstVaapiEncoderStatus ret = GST_VAAPI_ENCODER_STATUS_ERROR_UNKNOWN;
GstVaapiSurfaceProxy *reconstruct = NULL;
reconstruct = gst_vaapi_encoder_create_surface (base_encoder);
g_assert (GST_VAAPI_SURFACE_PROXY_SURFACE (reconstruct));
if (!ensure_sequence (encoder, picture))
goto error;
if (!ensure_misc_params (encoder, picture))
goto error;
if (!ensure_picture (encoder, picture, codedbuf, reconstruct))
goto error;
if (!ensure_quantization_table (encoder, picture))
goto error;
if (!gst_vaapi_enc_picture_encode (picture))
goto error;
if (reconstruct) {
if (picture->type == GST_VAAPI_PICTURE_TYPE_I)
clear_references (encoder);
push_reference (encoder, reconstruct);
}
return GST_VAAPI_ENCODER_STATUS_SUCCESS;
/* ERRORS */
error:
{
if (reconstruct)
gst_vaapi_encoder_release_surface (GST_VAAPI_ENCODER (encoder),
reconstruct);
return ret;
}
}
static GstVaapiEncoderStatus
gst_vaapi_encoder_vp8_flush (GstVaapiEncoder * base_encoder)
{
return GST_VAAPI_ENCODER_STATUS_SUCCESS;
}
static GstVaapiEncoderStatus
gst_vaapi_encoder_vp8_reordering (GstVaapiEncoder * base_encoder,
GstVideoCodecFrame * frame, GstVaapiEncPicture ** output)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
GstVaapiEncPicture *picture = NULL;
GstVaapiEncoderStatus status = GST_VAAPI_ENCODER_STATUS_SUCCESS;
if (!frame)
return GST_VAAPI_ENCODER_STATUS_NO_SURFACE;
picture = GST_VAAPI_ENC_PICTURE_NEW (VP8, encoder, frame);
if (!picture) {
GST_WARNING ("create VP8 picture failed, frame timestamp:%"
GST_TIME_FORMAT, GST_TIME_ARGS (frame->pts));
return GST_VAAPI_ENCODER_STATUS_ERROR_ALLOCATION_FAILED;
}
if (encoder->frame_num >= base_encoder->keyframe_period) {
encoder->frame_num = 0;
clear_references (encoder);
}
if (encoder->frame_num == 0) {
picture->type = GST_VAAPI_PICTURE_TYPE_I;
GST_VIDEO_CODEC_FRAME_SET_SYNC_POINT (frame);
} else {
picture->type = GST_VAAPI_PICTURE_TYPE_P;
}
encoder->frame_num++;
*output = picture;
return status;
}
static GstVaapiEncoderStatus
gst_vaapi_encoder_vp8_reconfigure (GstVaapiEncoder * base_encoder)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
GstVaapiEncoderStatus status;
status = ensure_profile (encoder);
if (status != GST_VAAPI_ENCODER_STATUS_SUCCESS)
return status;
if (!ensure_bitrate (encoder))
goto error;
return set_context_info (base_encoder);
/* ERRORS */
error:
{
return GST_VAAPI_ENCODER_STATUS_ERROR_OPERATION_FAILED;
}
}
static gboolean
gst_vaapi_encoder_vp8_init (GstVaapiEncoder * base_encoder)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
encoder->frame_num = 0;
encoder->last_ref = NULL;
encoder->golden_ref = NULL;
encoder->alt_ref = NULL;
return TRUE;
}
static void
gst_vaapi_encoder_vp8_finalize (GstVaapiEncoder * base_encoder)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
clear_references (encoder);
}
static GstVaapiEncoderStatus
gst_vaapi_encoder_vp8_set_property (GstVaapiEncoder * base_encoder,
gint prop_id, const GValue * value)
{
GstVaapiEncoderVP8 *const encoder = GST_VAAPI_ENCODER_VP8_CAST (base_encoder);
switch (prop_id) {
case GST_VAAPI_ENCODER_VP8_PROP_LOOP_FILTER_LEVEL:
encoder->loop_filter_level = g_value_get_uint (value);
break;
case GST_VAAPI_ENCODER_VP8_PROP_SHARPNESS_LEVEL:
encoder->sharpness_level = g_value_get_uint (value);
break;
case GST_VAAPI_ENCODER_VP8_PROP_YAC_Q_INDEX:
encoder->yac_qi = g_value_get_uint (value);
break;
default:
return GST_VAAPI_ENCODER_STATUS_ERROR_INVALID_PARAMETER;
}
return GST_VAAPI_ENCODER_STATUS_SUCCESS;
}
GST_VAAPI_ENCODER_DEFINE_CLASS_DATA (VP8);
static inline const GstVaapiEncoderClass *
gst_vaapi_encoder_vp8_class (void)
{
static const GstVaapiEncoderClass GstVaapiEncoderVP8Class = {
GST_VAAPI_ENCODER_CLASS_INIT (VP8, vp8),
.set_property = gst_vaapi_encoder_vp8_set_property,
};
return &GstVaapiEncoderVP8Class;
}
/**
* gst_vaapi_encoder_vp8_new:
* @display: a #GstVaapiDisplay
*
* Creates a new #GstVaapiEncoder for VP8 encoding.
*
* Return value: the newly allocated #GstVaapiEncoder object
*/
GstVaapiEncoder *
gst_vaapi_encoder_vp8_new (GstVaapiDisplay * display)
{
return gst_vaapi_encoder_new (gst_vaapi_encoder_vp8_class (), display);
}
/**
* gst_vaapi_encoder_vp8_get_default_properties:
*
* Determines the set of common and vp8 specific encoder properties.
* The caller owns an extra reference to the resulting array of
* #GstVaapiEncoderPropInfo elements, so it shall be released with
* g_ptr_array_unref() after usage.
*
* Return value: the set of encoder properties for #GstVaapiEncoderVP8,
* or %NULL if an error occurred.
*/
GPtrArray *
gst_vaapi_encoder_vp8_get_default_properties (void)
{
const GstVaapiEncoderClass *const klass = gst_vaapi_encoder_vp8_class ();
GPtrArray *props;
props = gst_vaapi_encoder_properties_get_default (klass);
if (!props)
return NULL;
GST_VAAPI_ENCODER_PROPERTIES_APPEND (props,
GST_VAAPI_ENCODER_VP8_PROP_LOOP_FILTER_LEVEL,
g_param_spec_uint ("loop-filter-level",
"Loop Filter Level",
"Controls the deblocking filter strength",
0, 63, DEFAULT_LOOP_FILTER_LEVEL,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
GST_VAAPI_ENCODER_PROPERTIES_APPEND (props,
GST_VAAPI_ENCODER_VP8_PROP_SHARPNESS_LEVEL,
g_param_spec_uint ("sharpness-level",
"Sharpness Level",
"Controls the deblocking filter sensitivity",
0, 7, DEFAULT_SHARPNESS_LEVEL,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
GST_VAAPI_ENCODER_PROPERTIES_APPEND (props,
GST_VAAPI_ENCODER_VP8_PROP_YAC_Q_INDEX,
g_param_spec_uint ("yac-qi",
"Luma AC Quant Table index",
"Quantization Table index for Luma AC Coefficients, (in default case, yac_qi=4 for key frames and yac_qi=40 for P frames)",
0, 127, DEFAULT_YAC_QI, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
return props;
}