/*
 *  gstvaapidecoder.c - VA decoder abstraction
 *
 *  Copyright (C) 2010-2011 Splitted-Desktop Systems
 *  Copyright (C) 2011-2013 Intel Corporation
 *
 *  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
 */

/**
 * SECTION:gstvaapidecoder
 * @short_description: VA decoder abstraction
 */

#include "sysdeps.h"
#include "gstvaapicompat.h"
#include "gstvaapidecoder.h"
#include "gstvaapidecoder_priv.h"
#include "gstvaapiparser_frame.h"
#include "gstvaapisurfaceproxy_priv.h"
#include "gstvaapiutils.h"

#define DEBUG 1
#include "gstvaapidebug.h"

static void
drop_frame(GstVaapiDecoder *decoder, GstVideoCodecFrame *frame);

static void
parser_state_finalize(GstVaapiParserState *ps)
{
    if (ps->input_adapter) {
        gst_adapter_clear(ps->input_adapter);
        g_object_unref(ps->input_adapter);
        ps->input_adapter = NULL;
    }

    if (ps->output_adapter) {
        gst_adapter_clear(ps->output_adapter);
        g_object_unref(ps->output_adapter);
        ps->output_adapter = NULL;
    }

    if (ps->next_unit_pending) {
        gst_vaapi_decoder_unit_clear(&ps->next_unit);
        ps->next_unit_pending = FALSE;
    }
}

static gboolean
parser_state_init(GstVaapiParserState *ps)
{
    memset(ps, 0, sizeof(*ps));

    ps->input_adapter = gst_adapter_new();
    if (!ps->input_adapter)
        return FALSE;

    ps->output_adapter = gst_adapter_new();
    if (!ps->output_adapter)
        return FALSE;
    return TRUE;
}

static void
parser_state_prepare(GstVaapiParserState *ps, GstAdapter *adapter)
{
    /* XXX: check we really have a continuity from the previous call */
    if (ps->current_adapter != adapter)
        goto reset;
    return;

reset:
    ps->current_adapter = adapter;
    ps->input_offset2 = -1;
}

static gboolean
push_buffer(GstVaapiDecoder *decoder, GstBuffer *buffer)
{
    if (!buffer) {
        buffer = gst_buffer_new();
        if (!buffer)
            return FALSE;
        GST_BUFFER_FLAG_SET(buffer, GST_BUFFER_FLAG_EOS);
    }

    GST_DEBUG("queue encoded data buffer %p (%d bytes)",
              buffer, gst_buffer_get_size(buffer));

    g_async_queue_push(decoder->buffers, buffer);
    return TRUE;
}

static GstBuffer *
pop_buffer(GstVaapiDecoder *decoder)
{
    GstBuffer *buffer;

    buffer = g_async_queue_try_pop(decoder->buffers);
    if (!buffer)
        return NULL;

    GST_DEBUG("dequeue buffer %p for decoding (%d bytes)",
              buffer, gst_buffer_get_size(buffer));

    return buffer;
}

static GstVaapiDecoderStatus
do_parse(GstVaapiDecoder *decoder,
    GstVideoCodecFrame *base_frame, GstAdapter *adapter, gboolean at_eos,
    guint *got_unit_size_ptr, gboolean *got_frame_ptr)
{
    GstVaapiParserState * const ps = &decoder->parser_state;
    GstVaapiParserFrame *frame;
    GstVaapiDecoderUnit *unit;
    GstVaapiDecoderStatus status;

    *got_unit_size_ptr = 0;
    *got_frame_ptr = FALSE;

    frame = gst_video_codec_frame_get_user_data(base_frame);
    if (!frame) {
        GstVideoCodecState * const codec_state = decoder->codec_state;
        frame = gst_vaapi_parser_frame_new(codec_state->info.width,
            codec_state->info.height);
        if (!frame)
            return GST_VAAPI_DECODER_STATUS_ERROR_ALLOCATION_FAILED;
        gst_video_codec_frame_set_user_data(base_frame,
            frame, (GDestroyNotify)gst_vaapi_mini_object_unref);
    }

    parser_state_prepare(ps, adapter);

    unit = &ps->next_unit;
    if (ps->next_unit_pending) {
        ps->next_unit_pending = FALSE;
        goto got_unit;
    }
    gst_vaapi_decoder_unit_init(unit);

    ps->current_frame = base_frame;
    status = GST_VAAPI_DECODER_GET_CLASS(decoder)->parse(decoder,
        adapter, at_eos, unit);
    if (status != GST_VAAPI_DECODER_STATUS_SUCCESS) {
        if (at_eos && frame->units->len > 0 &&
            status == GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA) {
            /* XXX: assume the frame is complete at <EOS> */
            *got_frame_ptr = TRUE;
            return GST_VAAPI_DECODER_STATUS_SUCCESS;
        }
        return status;
    }

    if (GST_VAAPI_DECODER_UNIT_IS_FRAME_START(unit) && frame->units->len > 0) {
        ps->next_unit_pending = TRUE;
        *got_frame_ptr = TRUE;
        return GST_VAAPI_DECODER_STATUS_SUCCESS;
    }

got_unit:
    gst_vaapi_parser_frame_append_unit(frame, unit);
    *got_unit_size_ptr = unit->size;
    *got_frame_ptr = GST_VAAPI_DECODER_UNIT_IS_FRAME_END(unit);
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

static GstVaapiDecoderStatus
do_decode_units(GstVaapiDecoder *decoder, GArray *units)
{
    GstVaapiDecoderClass * const klass = GST_VAAPI_DECODER_GET_CLASS(decoder);
    GstVaapiDecoderStatus status;
    guint i;

    for (i = 0; i < units->len; i++) {
        GstVaapiDecoderUnit * const unit =
            &g_array_index(units, GstVaapiDecoderUnit, i);
        if (GST_VAAPI_DECODER_UNIT_IS_SKIPPED(unit))
            continue;
        status = klass->decode(decoder, unit);
        if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
            return status;
    }
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

static GstVaapiDecoderStatus
do_decode_1(GstVaapiDecoder *decoder, GstVaapiParserFrame *frame)
{
    GstVaapiDecoderClass * const klass = GST_VAAPI_DECODER_GET_CLASS(decoder);
    GstVaapiDecoderStatus status;

    if (frame->pre_units->len > 0) {
        status = do_decode_units(decoder, frame->pre_units);
        if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
            return status;
    }

    if (frame->units->len > 0) {
        if (klass->start_frame) {
            GstVaapiDecoderUnit * const unit =
                &g_array_index(frame->units, GstVaapiDecoderUnit, 0);
            status = klass->start_frame(decoder, unit);
            if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
                return status;
        }

        status = do_decode_units(decoder, frame->units);
        if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
            return status;

        if (klass->end_frame) {
            status = klass->end_frame(decoder);
            if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
                return status;
        }
    }

    if (frame->post_units->len > 0) {
        status = do_decode_units(decoder, frame->post_units);
        if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
            return status;
    }

    /* Drop frame if there is no slice data unit in there */
    if (G_UNLIKELY(frame->units->len == 0))
        return GST_VAAPI_DECODER_STATUS_DROP_FRAME;
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

static inline GstVaapiDecoderStatus
do_decode(GstVaapiDecoder *decoder, GstVideoCodecFrame *base_frame)
{
    GstVaapiParserState * const ps = &decoder->parser_state;
    GstVaapiParserFrame * const frame = base_frame->user_data;
    GstVaapiDecoderStatus status;

    ps->current_frame = base_frame;

    gst_vaapi_parser_frame_ref(frame);
    status = do_decode_1(decoder, frame);
    gst_vaapi_parser_frame_unref(frame);

    switch ((guint)status) {
    case GST_VAAPI_DECODER_STATUS_DROP_FRAME:
        drop_frame(decoder, base_frame);
        status = GST_VAAPI_DECODER_STATUS_SUCCESS;
        break;
    }
    return status;
}

static inline GstVaapiDecoderStatus
do_flush(GstVaapiDecoder *decoder)
{
    GstVaapiDecoderClass * const klass = GST_VAAPI_DECODER_GET_CLASS(decoder);

    if (klass->flush)
        return klass->flush(decoder);
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

static GstVaapiDecoderStatus
decode_step(GstVaapiDecoder *decoder)
{
    GstVaapiParserState * const ps = &decoder->parser_state;
    GstVaapiDecoderStatus status;
    GstBuffer *buffer;
    gboolean got_frame;
    guint got_unit_size, input_size;

    status = gst_vaapi_decoder_check_status(decoder);
    if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
        return status;

    /* Fill adapter with all buffers we have in the queue */
    for (;;) {
        buffer = pop_buffer(decoder);
        if (!buffer)
            break;

        ps->at_eos = GST_BUFFER_IS_EOS(buffer);
        if (!ps->at_eos)
            gst_adapter_push(ps->input_adapter, buffer);
    }

    /* Parse and decode all decode units */
    input_size = gst_adapter_available(ps->input_adapter);
    if (input_size == 0) {
        if (ps->at_eos)
            return GST_VAAPI_DECODER_STATUS_END_OF_STREAM;
        return GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA;
    }

    do {
        if (!ps->current_frame) {
            ps->current_frame = g_slice_new0(GstVideoCodecFrame);
            if (!ps->current_frame)
                return GST_VAAPI_DECODER_STATUS_ERROR_ALLOCATION_FAILED;
            ps->current_frame->ref_count = 1;
        }

        status = do_parse(decoder, ps->current_frame, ps->input_adapter,
            ps->at_eos, &got_unit_size, &got_frame);
        GST_DEBUG("parse frame (status = %d)", status);
        if (status != GST_VAAPI_DECODER_STATUS_SUCCESS) {
            if (status == GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA && ps->at_eos)
                status = GST_VAAPI_DECODER_STATUS_END_OF_STREAM;
            break;
        }

        if (got_unit_size > 0) {
            buffer = gst_adapter_take_buffer(ps->input_adapter, got_unit_size);
            input_size -= got_unit_size;

            if (gst_adapter_available(ps->output_adapter) == 0) {
                ps->current_frame->pts =
                    gst_adapter_prev_timestamp(ps->input_adapter, NULL);
            }
            gst_adapter_push(ps->output_adapter, buffer);
        }

        if (got_frame) {
            ps->current_frame->input_buffer = gst_adapter_take_buffer(
                ps->output_adapter,
                gst_adapter_available(ps->output_adapter));

            status = do_decode(decoder, ps->current_frame);
            GST_DEBUG("decode frame (status = %d)", status);

            gst_video_codec_frame_unref(ps->current_frame);
            ps->current_frame = NULL;
            break;
        }
    } while (input_size > 0);
    return status;
}

static void
drop_frame(GstVaapiDecoder *decoder, GstVideoCodecFrame *frame)
{
    GST_DEBUG("drop frame %d", frame->system_frame_number);

    /* no surface proxy */
    gst_video_codec_frame_set_user_data(frame, NULL, NULL);

    frame->pts = GST_CLOCK_TIME_NONE;
    GST_VIDEO_CODEC_FRAME_FLAG_SET(frame,
        GST_VIDEO_CODEC_FRAME_FLAG_DECODE_ONLY);

    g_async_queue_push(decoder->frames, gst_video_codec_frame_ref(frame));
}

static inline void
push_frame(GstVaapiDecoder *decoder, GstVideoCodecFrame *frame)
{
    GstVaapiSurfaceProxy * const proxy = frame->user_data;

    GST_DEBUG("queue decoded surface %" GST_VAAPI_ID_FORMAT,
              GST_VAAPI_ID_ARGS(GST_VAAPI_SURFACE_PROXY_SURFACE_ID(proxy)));

    g_async_queue_push(decoder->frames, gst_video_codec_frame_ref(frame));
}

static inline GstVideoCodecFrame *
pop_frame(GstVaapiDecoder *decoder, guint64 timeout)
{
    GstVideoCodecFrame *frame;
    GstVaapiSurfaceProxy *proxy;

    if (G_LIKELY(timeout > 0))
        frame = g_async_queue_timeout_pop(decoder->frames, timeout);
    else
        frame = g_async_queue_try_pop(decoder->frames);
    if (!frame)
        return NULL;

    proxy = frame->user_data;
    GST_DEBUG("dequeue decoded surface %" GST_VAAPI_ID_FORMAT,
              GST_VAAPI_ID_ARGS(GST_VAAPI_SURFACE_PROXY_SURFACE_ID(proxy)));

    return frame;
}

static gboolean
set_caps(GstVaapiDecoder *decoder, const GstCaps *caps)
{
    GstVideoCodecState * const codec_state = decoder->codec_state;
    GstStructure * const structure = gst_caps_get_structure(caps, 0);
    GstVaapiProfile profile;
    const GValue *v_codec_data;

    profile = gst_vaapi_profile_from_caps(caps);
    if (!profile)
        return FALSE;

    decoder->codec = gst_vaapi_profile_get_codec(profile);
    if (!decoder->codec)
        return FALSE;

    if (!gst_video_info_from_caps(&codec_state->info, caps))
        return FALSE;

    codec_state->caps = gst_caps_copy(caps);

    v_codec_data = gst_structure_get_value(structure, "codec_data");
    if (v_codec_data)
        gst_buffer_replace(&codec_state->codec_data,
            gst_value_get_buffer(v_codec_data));
    return TRUE;
}

static inline GstCaps *
get_caps(GstVaapiDecoder *decoder)
{
    return GST_VAAPI_DECODER_CODEC_STATE(decoder)->caps;
}

static void
notify_codec_state_changed(GstVaapiDecoder *decoder)
{
    if (decoder->codec_state_changed_func)
        decoder->codec_state_changed_func(decoder, decoder->codec_state,
            decoder->codec_state_changed_data);
}

void
gst_vaapi_decoder_finalize(GstVaapiDecoder *decoder)
{
    const GstVaapiDecoderClass * const klass =
        GST_VAAPI_DECODER_GET_CLASS(decoder);

    if (klass->destroy)
        klass->destroy(decoder);

    gst_video_codec_state_unref(decoder->codec_state);
    decoder->codec_state = NULL;

    parser_state_finalize(&decoder->parser_state);
 
    if (decoder->buffers) {
        g_async_queue_unref(decoder->buffers);
        decoder->buffers = NULL;
    }

    if (decoder->frames) {
        g_async_queue_unref(decoder->frames);
        decoder->frames = NULL;
    }

    gst_vaapi_object_replace(&decoder->context, NULL);
    decoder->va_context = VA_INVALID_ID;

    gst_vaapi_display_replace(&decoder->display, NULL);
    decoder->va_display = NULL;
}

static gboolean
gst_vaapi_decoder_init(GstVaapiDecoder *decoder, GstVaapiDisplay *display,
    GstCaps *caps)
{
    const GstVaapiDecoderClass * const klass =
        GST_VAAPI_DECODER_GET_CLASS(decoder);
    GstVideoCodecState *codec_state;
    guint sub_size;

    parser_state_init(&decoder->parser_state);

    codec_state = g_slice_new0(GstVideoCodecState);
    codec_state->ref_count = 1;
    gst_video_info_init(&codec_state->info);

    decoder->user_data   = NULL;
    decoder->display     = gst_vaapi_display_ref(display);
    decoder->va_display  = GST_VAAPI_DISPLAY_VADISPLAY(display);
    decoder->context     = NULL;
    decoder->va_context  = VA_INVALID_ID;
    decoder->codec       = 0;
    decoder->codec_state = codec_state;
    decoder->codec_state_changed_func = NULL;
    decoder->codec_state_changed_data = NULL;

    decoder->buffers = g_async_queue_new_full((GDestroyNotify)gst_buffer_unref);
    decoder->frames  = g_async_queue_new_full((GDestroyNotify)
        gst_video_codec_frame_unref);

    if (!set_caps(decoder, caps))
        return FALSE;

    sub_size = GST_VAAPI_MINI_OBJECT_CLASS(klass)->size - sizeof(*decoder);
    if (sub_size > 0)
        memset(((guchar *)decoder) + sizeof(*decoder), 0, sub_size);

    if (klass->create && !klass->create(decoder))
        return FALSE;
    return TRUE;
}

GstVaapiDecoder *
gst_vaapi_decoder_new(const GstVaapiDecoderClass *klass,
    GstVaapiDisplay *display, GstCaps *caps)
{
    GstVaapiDecoder *decoder;

    g_return_val_if_fail(GST_VAAPI_IS_DISPLAY(display), NULL);
    g_return_val_if_fail(GST_IS_CAPS(caps), NULL);

    decoder = (GstVaapiDecoder *)
        gst_vaapi_mini_object_new(GST_VAAPI_MINI_OBJECT_CLASS(klass));
    if (!decoder)
        return NULL;

    if (!gst_vaapi_decoder_init(decoder, display, caps))
        goto error;
    return decoder;

error:
    gst_vaapi_decoder_unref(decoder);
    return NULL;
}

/**
 * gst_vaapi_decoder_ref:
 * @decoder: a #GstVaapiDecoder
 *
 * Atomically increases the reference count of the given @decoder by one.
 *
 * Returns: The same @decoder argument
 */
GstVaapiDecoder *
gst_vaapi_decoder_ref(GstVaapiDecoder *decoder)
{
    return gst_vaapi_object_ref(decoder);
}

/**
 * gst_vaapi_decoder_unref:
 * @decoder: a #GstVaapiDecoder
 *
 * Atomically decreases the reference count of the @decoder by one. If
 * the reference count reaches zero, the decoder will be free'd.
 */
void
gst_vaapi_decoder_unref(GstVaapiDecoder *decoder)
{
    gst_vaapi_object_unref(decoder);
}

/**
 * gst_vaapi_decoder_replace:
 * @old_decoder_ptr: a pointer to a #GstVaapiDecoder
 * @new_decoder: a #GstVaapiDecoder
 *
 * Atomically replaces the decoder decoder held in @old_decoder_ptr
 * with @new_decoder. This means that @old_decoder_ptr shall reference
 * a valid decoder. However, @new_decoder can be NULL.
 */
void
gst_vaapi_decoder_replace(GstVaapiDecoder **old_decoder_ptr,
    GstVaapiDecoder *new_decoder)
{
    gst_vaapi_object_replace(old_decoder_ptr, new_decoder);
}

/**
 * gst_vaapi_decoder_get_user_data:
 * @decoder: a #GstVaapiDecoder
 *
 * Retrieves the user-defined data associated with the @decoder, if any.
 *
 * Return value: the user-defined data associated with the @decoder
 */
gpointer
gst_vaapi_decoder_get_user_data(GstVaapiDecoder *decoder)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder), NULL);

    return decoder->user_data;
}

/**
 * gst_vaapi_decoder_set_user_data:
 * @decoder: a #GstVaapiDecoder
 * @user_data: the pointer to user-defined data
 *
 * Associates user-defined @user_data to the @decoder. Retrieve the
 * attached value with gst_vaapi_decoder_get_user_data() function.
 */
void
gst_vaapi_decoder_set_user_data(GstVaapiDecoder *decoder, gpointer user_data)
{
    g_return_if_fail(GST_VAAPI_IS_DECODER(decoder));

    decoder->user_data = user_data;
}

/**
 * gst_vaapi_decoder_get_codec:
 * @decoder: a #GstVaapiDecoder
 *
 * Retrieves the @decoder codec type.
 *
 * Return value: the #GstVaapiCodec type for @decoder
 */
GstVaapiCodec
gst_vaapi_decoder_get_codec(GstVaapiDecoder *decoder)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder), (GstVaapiCodec)0);

    return decoder->codec;
}

/**
 * gst_vaapi_decoder_get_codec_state:
 * @decoder: a #GstVaapiDecoder
 *
 * Retrieves the @decoder codec state. The decoder owns the returned
 * #GstVideoCodecState structure, so use gst_video_codec_state_ref()
 * whenever necessary.
 *
 * Return value: the #GstVideoCodecState object for @decoder
 */
GstVideoCodecState *
gst_vaapi_decoder_get_codec_state(GstVaapiDecoder *decoder)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder), NULL);

    return GST_VAAPI_DECODER_CODEC_STATE(decoder);
}

/**
 * gst_vaapi_decoder_set_codec_state_changed_func:
 * @decoder: a #GstVaapiDecoder
 * @func: the function to call when codec state changed
 * @user_data: a pointer to user-defined data
 *
 * Sets @func as the function to call whenever the @decoder codec
 * state changes.
 */
void
gst_vaapi_decoder_set_codec_state_changed_func(GstVaapiDecoder *decoder,
    GstVaapiDecoderStateChangedFunc func, gpointer user_data)
{
    g_return_if_fail(GST_VAAPI_IS_DECODER(decoder));

    decoder->codec_state_changed_func = func;
    decoder->codec_state_changed_data = user_data;
}

/**
 * gst_vaapi_decoder_get_caps:
 * @decoder: a #GstVaapiDecoder
 *
 * Retrieves the @decoder caps. The decoder owns the returned caps, so
 * use gst_caps_ref() whenever necessary.
 *
 * Return value: the @decoder caps
 */
GstCaps *
gst_vaapi_decoder_get_caps(GstVaapiDecoder *decoder)
{
    return get_caps(decoder);
}

/**
 * gst_vaapi_decoder_put_buffer:
 * @decoder: a #GstVaapiDecoder
 * @buf: a #GstBuffer
 *
 * Queues a #GstBuffer to the HW decoder. The decoder holds a
 * reference to @buf.
 *
 * Caller can notify an End-Of-Stream with @buf set to %NULL. However,
 * if an empty buffer is passed, i.e. a buffer with %NULL data pointer
 * or size equals to zero, then the function ignores this buffer and
 * returns %TRUE.
 *
 * Return value: %TRUE on success
 */
gboolean
gst_vaapi_decoder_put_buffer(GstVaapiDecoder *decoder, GstBuffer *buf)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder), FALSE);

    if (buf) {
        if (gst_buffer_get_size(buf) == 0)
            return TRUE;
        buf = gst_buffer_ref(buf);
    }
    return push_buffer(decoder, buf);
}

/**
 * gst_vaapi_decoder_get_surface:
 * @decoder: a #GstVaapiDecoder
 * @out_proxy_ptr: the next decoded surface as a #GstVaapiSurfaceProxy
 *
 * Flushes encoded buffers to the decoder and returns a decoded
 * surface, if any.
 *
 * On successful return, *@out_proxy_ptr contains the decoded surface
 * as a #GstVaapiSurfaceProxy. The caller owns this object, so
 * gst_vaapi_surface_proxy_unref() shall be called after usage.
 *
 * Return value: a #GstVaapiDecoderStatus
 */
GstVaapiDecoderStatus
gst_vaapi_decoder_get_surface(GstVaapiDecoder *decoder,
    GstVaapiSurfaceProxy **out_proxy_ptr)
{
    GstVideoCodecFrame *frame;
    GstVaapiDecoderStatus status;

    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder),
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(out_proxy_ptr != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);

    do {
        frame = pop_frame(decoder, 0);
        while (frame) {
            if (!GST_VIDEO_CODEC_FRAME_IS_DECODE_ONLY(frame)) {
                GstVaapiSurfaceProxy * const proxy = frame->user_data;
                proxy->timestamp = frame->pts;
                proxy->duration = frame->duration;
                *out_proxy_ptr = gst_vaapi_surface_proxy_ref(proxy);
                gst_video_codec_frame_unref(frame);
                return GST_VAAPI_DECODER_STATUS_SUCCESS;
            }
            gst_video_codec_frame_unref(frame);
            frame = pop_frame(decoder, 0);
        }
        status = decode_step(decoder);
    } while (status == GST_VAAPI_DECODER_STATUS_SUCCESS);

    *out_proxy_ptr = NULL;
    return status;
}

/**
 * gst_vaapi_decoder_get_frame:
 * @decoder: a #GstVaapiDecoder
 * @out_frame_ptr: the next decoded frame as a #GstVideoCodecFrame
 *
 * On successful return, *@out_frame_ptr contains the next decoded
 * frame available as a #GstVideoCodecFrame. The caller owns this
 * object, so gst_video_codec_frame_unref() shall be called after
 * usage. Otherwise, @GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA is
 * returned if no decoded frame is available.
 *
 * The actual surface is available as a #GstVaapiSurfaceProxy attached
 * to the user-data anchor of the output frame. Ownership of the proxy
 * is transferred to the frame.
 *
 * This is equivalent to gst_vaapi_decoder_get_frame_with_timeout()
 * with a timeout value of zero.
 *
 * Return value: a #GstVaapiDecoderStatus
 */
GstVaapiDecoderStatus
gst_vaapi_decoder_get_frame(GstVaapiDecoder *decoder,
    GstVideoCodecFrame **out_frame_ptr)
{
    return gst_vaapi_decoder_get_frame_with_timeout(decoder, out_frame_ptr, 0);
}

/**
 * gst_vaapi_decoder_get_frame_with_timeout:
 * @decoder: a #GstVaapiDecoder
 * @out_frame_ptr: the next decoded frame as a #GstVideoCodecFrame
 * @timeout: the number of microseconds to wait for the frame, at most
 *
 * On successful return, *@out_frame_ptr contains the next decoded
 * frame available as a #GstVideoCodecFrame. The caller owns this
 * object, so gst_video_codec_frame_unref() shall be called after
 * usage. Otherwise, @GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA is
 * returned if no decoded frame is available.
 *
 * The actual surface is available as a #GstVaapiSurfaceProxy attached
 * to the user-data anchor of the output frame. Ownership of the proxy
 * is transferred to the frame.
 *
 * Return value: a #GstVaapiDecoderStatus
 */
GstVaapiDecoderStatus
gst_vaapi_decoder_get_frame_with_timeout(GstVaapiDecoder *decoder,
    GstVideoCodecFrame **out_frame_ptr, guint64 timeout)
{
    GstVideoCodecFrame *out_frame;

    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder),
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(out_frame_ptr != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);

    out_frame = pop_frame(decoder, timeout);
    if (!out_frame)
        return GST_VAAPI_DECODER_STATUS_ERROR_NO_DATA;

#if !GST_CHECK_VERSION(1,0,0)
    if (!GST_VIDEO_CODEC_FRAME_IS_DECODE_ONLY(out_frame)) {
        const guint flags = GST_VAAPI_SURFACE_PROXY_FLAGS(out_frame->user_data);
        guint out_flags = 0;

        if (flags & GST_VAAPI_SURFACE_PROXY_FLAG_TFF)
            out_flags |= GST_VIDEO_CODEC_FRAME_FLAG_TFF;
        if (flags & GST_VAAPI_SURFACE_PROXY_FLAG_RFF)
            out_flags |= GST_VIDEO_CODEC_FRAME_FLAG_RFF;
        if (flags & GST_VAAPI_SURFACE_PROXY_FLAG_ONEFIELD)
            out_flags |= GST_VIDEO_CODEC_FRAME_FLAG_ONEFIELD;
        GST_VIDEO_CODEC_FRAME_FLAG_SET(out_frame, out_flags);
    }
#endif

    *out_frame_ptr = out_frame;
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

void
gst_vaapi_decoder_set_picture_size(
    GstVaapiDecoder    *decoder,
    guint               width,
    guint               height
)
{
    GstVideoCodecState * const codec_state = decoder->codec_state;
    gboolean size_changed = FALSE;

    if (codec_state->info.width != width) {
        GST_DEBUG("picture width changed to %d", width);
        codec_state->info.width = width;
        gst_caps_set_simple(codec_state->caps,
            "width", G_TYPE_INT, width, NULL);
        size_changed = TRUE;
    }

    if (codec_state->info.height != height) {
        GST_DEBUG("picture height changed to %d", height);
        codec_state->info.height = height;
        gst_caps_set_simple(codec_state->caps,
            "height", G_TYPE_INT, height, NULL);
        size_changed = TRUE;
    }

    if (size_changed)
        notify_codec_state_changed(decoder);
}

void
gst_vaapi_decoder_set_framerate(
    GstVaapiDecoder    *decoder,
    guint               fps_n,
    guint               fps_d
)
{
    GstVideoCodecState * const codec_state = decoder->codec_state;

    if (!fps_n || !fps_d)
        return;

    if (codec_state->info.fps_n != fps_n || codec_state->info.fps_d != fps_d) {
        GST_DEBUG("framerate changed to %u/%u", fps_n, fps_d);
        codec_state->info.fps_n = fps_n;
        codec_state->info.fps_d = fps_d;
        gst_caps_set_simple(codec_state->caps,
            "framerate", GST_TYPE_FRACTION, fps_n, fps_d, NULL);
        notify_codec_state_changed(decoder);
    }
}

void
gst_vaapi_decoder_set_pixel_aspect_ratio(
    GstVaapiDecoder    *decoder,
    guint               par_n,
    guint               par_d
)
{
    GstVideoCodecState * const codec_state = decoder->codec_state;

    if (!par_n || !par_d)
        return;

    if (codec_state->info.par_n != par_n || codec_state->info.par_d != par_d) {
        GST_DEBUG("pixel-aspect-ratio changed to %u/%u", par_n, par_d);
        codec_state->info.par_n = par_n;
        codec_state->info.par_d = par_d;
        gst_caps_set_simple(codec_state->caps,
            "pixel-aspect-ratio", GST_TYPE_FRACTION, par_n, par_d, NULL);
        notify_codec_state_changed(decoder);
    }
}

static const gchar *
gst_interlace_mode_to_string(GstVideoInterlaceMode mode)
{
    switch (mode) {
    case GST_VIDEO_INTERLACE_MODE_PROGRESSIVE:  return "progressive";
    case GST_VIDEO_INTERLACE_MODE_INTERLEAVED:  return "interleaved";
    case GST_VIDEO_INTERLACE_MODE_MIXED:        return "mixed";
    }
    return "<unknown>";
}

void
gst_vaapi_decoder_set_interlace_mode(GstVaapiDecoder *decoder,
    GstVideoInterlaceMode mode)
{
    GstVideoCodecState * const codec_state = decoder->codec_state;

    if (codec_state->info.interlace_mode != mode) {
        GST_DEBUG("interlace mode changed to %s",
                  gst_interlace_mode_to_string(mode));
        codec_state->info.interlace_mode = mode;
        gst_caps_set_simple(codec_state->caps, "interlaced",
            G_TYPE_BOOLEAN, mode != GST_VIDEO_INTERLACE_MODE_PROGRESSIVE, NULL);
        notify_codec_state_changed(decoder);
    }
}

void
gst_vaapi_decoder_set_interlaced(GstVaapiDecoder *decoder, gboolean interlaced)
{
    gst_vaapi_decoder_set_interlace_mode(decoder,
        (interlaced ?
         GST_VIDEO_INTERLACE_MODE_INTERLEAVED :
         GST_VIDEO_INTERLACE_MODE_PROGRESSIVE));
}

gboolean
gst_vaapi_decoder_ensure_context(
    GstVaapiDecoder     *decoder,
    GstVaapiContextInfo *cip
)
{
    gst_vaapi_decoder_set_picture_size(decoder, cip->width, cip->height);

    if (decoder->context) {
        if (!gst_vaapi_context_reset_full(decoder->context, cip))
            return FALSE;
    }
    else {
        decoder->context = gst_vaapi_context_new_full(decoder->display, cip);
        if (!decoder->context)
            return FALSE;
    }
    decoder->va_context = gst_vaapi_context_get_id(decoder->context);
    return TRUE;
}

void
gst_vaapi_decoder_push_frame(GstVaapiDecoder *decoder,
    GstVideoCodecFrame *frame)
{
    push_frame(decoder, frame);
}

GstVaapiDecoderStatus
gst_vaapi_decoder_check_status(GstVaapiDecoder *decoder)
{
    if (decoder->context &&
        gst_vaapi_context_get_surface_count(decoder->context) < 1)
        return GST_VAAPI_DECODER_STATUS_ERROR_NO_SURFACE;
    return GST_VAAPI_DECODER_STATUS_SUCCESS;
}

GstVaapiDecoderStatus
gst_vaapi_decoder_parse(GstVaapiDecoder *decoder,
    GstVideoCodecFrame *base_frame, GstAdapter *adapter, gboolean at_eos,
    guint *got_unit_size_ptr, gboolean *got_frame_ptr)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder),
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(base_frame != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(adapter != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(got_unit_size_ptr != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(got_frame_ptr != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);

    return do_parse(decoder, base_frame, adapter, at_eos,
        got_unit_size_ptr, got_frame_ptr);
}

GstVaapiDecoderStatus
gst_vaapi_decoder_decode(GstVaapiDecoder *decoder, GstVideoCodecFrame *frame)
{
    GstVaapiDecoderStatus status;

    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder),
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(frame != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);
    g_return_val_if_fail(frame->user_data != NULL,
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);

    status = gst_vaapi_decoder_check_status(decoder);
    if (status != GST_VAAPI_DECODER_STATUS_SUCCESS)
        return status;
    return do_decode(decoder, frame);
}

GstVaapiDecoderStatus
gst_vaapi_decoder_flush(GstVaapiDecoder *decoder)
{
    g_return_val_if_fail(GST_VAAPI_IS_DECODER(decoder),
        GST_VAAPI_DECODER_STATUS_ERROR_INVALID_PARAMETER);

    return do_flush(decoder);
}

GstVaapiDecoderStatus
gst_vaapi_decoder_decode_codec_data(GstVaapiDecoder *decoder)
{
    GstVaapiDecoderClass * const klass = GST_VAAPI_DECODER_GET_CLASS(decoder);
    GstBuffer * const codec_data = GST_VAAPI_DECODER_CODEC_DATA(decoder);
    GstVaapiDecoderStatus status;
    GstMapInfo map_info;
    const guchar *buf;
    guint buf_size;

    if (!codec_data)
        return GST_VAAPI_DECODER_STATUS_SUCCESS;

    /* FIXME: add a meaningful error code? */
    if (!klass->decode_codec_data)
        return GST_VAAPI_DECODER_STATUS_SUCCESS;

    if (!gst_buffer_map(codec_data, &map_info, GST_MAP_READ)) {
        GST_ERROR("failed to map buffer");
        return GST_VAAPI_DECODER_STATUS_ERROR_UNKNOWN;
    }

    buf      = map_info.data;
    buf_size = map_info.size;
    if (G_LIKELY(buf && buf_size > 0))
        status = klass->decode_codec_data(decoder, buf, buf_size);
    else
        status = GST_VAAPI_DECODER_STATUS_SUCCESS;
    gst_buffer_unmap(codec_data, &map_info);
    return status;
}