From 6b56c541ed7dd271ad0aa6eb6412a8427f009525 Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.z...@intel.com>
Date: Tue, 21 Mar 2017 11:04:41 +0800
Subject: [PATCH] examples/vaapi_dec: Add a VA-API hwaccel decoding example.

Add a VA-API hwaccel decoding example.

Signed-off-by: Liu, Kaixuan <kaixuan....@intel.com>
Signed-off-by: Jun Zhao <jun.z...@intel.com>
---
 doc/examples/vaapi_dec.c | 346 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 346 insertions(+)
 create mode 100644 doc/examples/vaapi_dec.c

diff --git a/doc/examples/vaapi_dec.c b/doc/examples/vaapi_dec.c
new file mode 100644
index 0000000..f975d86
--- /dev/null
+++ b/doc/examples/vaapi_dec.c
@@ -0,0 +1,346 @@
+/*
+ * Video Acceleration API (video decoding) decode sample
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Intel VAAPI-accelerated decoding example.
+ *
+ * @example vaapi_dec.c
+ * This example shows how to do VAAPI-accelerated decoding with output
+ * frames from the VAAPI video surfaces.
+ */
+
+#include <stdio.h>
+#include <libavcodec/avcodec.h>
+#include <libavcodec/vaapi.h>
+#include <libavformat/avformat.h>
+#include <libswscale/swscale.h>
+#include <libavutil/pixdesc.h>
+#include <libavutil/hwcontext.h>
+#include <libavutil/opt.h>
+#include <libavutil/hwcontext_vaapi.h>
+#include <libavutil/avassert.h>
+#include <va/va.h>
+#include <va/va_x11.h>
+#include <va/va_drm.h>
+
+#define DEFAULT_SURFACES 20
+static enum AVPixelFormat decode_format = AV_PIX_FMT_NV12;
+static enum AVPixelFormat output_format = AV_PIX_FMT_NV12; /* default output 
format nv12 */
+static AVBufferRef *frames_ref = NULL;
+static AVBufferRef *device_ref = NULL;
+FILE *output_file = NULL;
+
+void decoder_uninit_vaapi(AVCodecContext *avctx, AVVAAPIDeviceContext *hwctx)
+{
+    if (hwctx) {
+        av_buffer_unref(&frames_ref);
+        av_buffer_unref(&device_ref);
+    }
+    return;
+}
+
+int decoder_init_vaapi(AVCodecContext *ctx)
+{
+    AVBufferRef *hw_device_ctx = NULL;
+    AVHWFramesContext *frames;
+    int err = 0;
+    char *dev_name = "/dev/dri/renderD128";
+    AVBufferRef *device_ref = NULL;
+    AVHWDeviceContext *device = NULL;
+    AVVAAPIDeviceContext *hwctx = NULL;
+
+    if ((err = av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI,
+                                      dev_name, NULL, 0)) < 0) {
+        fprintf(stderr, "Failed to create a VAAPI device.\n");
+        return err;
+    }
+
+    device_ref = av_buffer_ref(hw_device_ctx);
+    device = (AVHWDeviceContext *)device_ref->data;
+    hwctx = (AVVAAPIDeviceContext *)device->hwctx;
+
+    ctx->pix_fmt = output_format;
+    if (!(frames_ref = av_hwframe_ctx_alloc(device_ref))) {
+        fprintf(stderr, "Failed to create VAAPI frame context.\n");
+        err = AVERROR(ENOMEM);
+        goto fail;
+    }
+    frames = (AVHWFramesContext *)frames_ref->data;
+    frames->format    = AV_PIX_FMT_VAAPI;
+    frames->sw_format = decode_format;
+    frames->width     = ctx->coded_width;
+    frames->height    = ctx->coded_height;
+    frames->initial_pool_size = DEFAULT_SURFACES;
+    if ((err = av_hwframe_ctx_init(frames_ref)) < 0) {
+        fprintf(stderr, "Failed to initialize VAAPI frame.\n");
+        goto fail;
+    }
+
+    ctx->hw_frames_ctx = av_buffer_ref(frames_ref);
+    if (!ctx->hw_frames_ctx) {
+        err = AVERROR(ENOMEM);
+        fprintf(stderr, "Failed to ref VAAPI frame.\n");
+        goto fail;
+    }
+
+fail:
+    if (err < 0)
+        decoder_uninit_vaapi(ctx, hwctx);
+    return err;
+}
+
+static enum AVPixelFormat get_hw_vaapi_format(AVCodecContext *ctx,
+                                              const enum AVPixelFormat 
*pix_fmts)
+{
+    const enum AVPixelFormat *p;
+    int ret;
+
+    for (p = pix_fmts; *p != -1; p++) {
+        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(*p);
+        if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
+            break;
+
+        if (!(strstr(desc->name, "vaapi")))
+            continue;
+
+        if ((ret = decoder_init_vaapi(ctx)) < 0) {
+            fprintf(stderr, "hwaccel for decoder(VAAPI) cannot be 
initialized.\n");
+            return AV_PIX_FMT_NONE;
+        }
+        break;
+    }
+    return *p;
+}
+
+static int get_hw_vaapi_buffer(AVCodecContext *ctx, AVFrame *frame, int flags)
+{
+    int err;
+    if ((err = av_hwframe_get_buffer(frames_ref, frame, 0)) < 0)
+        av_log(NULL, AV_LOG_ERROR, "Failed to allocate decoder surface.\n");
+
+    return err;
+}
+
+int retrieve_data(AVFrame *input)
+{
+    AVFrame *output = 0;
+    int err;
+    av_assert0(input->format == AV_PIX_FMT_VAAPI);
+
+    if (output_format == AV_PIX_FMT_VAAPI)
+        return 0;
+
+    if (!(output = av_frame_alloc()))
+        return AVERROR(ENOMEM);
+    output->format = output_format;
+    if ((err = av_hwframe_transfer_data(output, input, 0)) < 0) {
+        fprintf(stderr, "Failed to transfer data to output frame: %d.\n", err);
+        goto fail;
+    }
+
+    if ((err = av_frame_copy_props(output, input)) < 0) {
+        av_frame_unref(output);
+        goto fail;
+    }
+
+    av_frame_unref(input);
+    av_frame_move_ref(input, output);
+    av_frame_free(&output);
+    return 0;
+
+fail:
+    av_frame_free(&output);
+    return err;
+}
+
+int write_frame(AVFrame *frame)
+{
+    int idx, size;
+    int width = frame->width;
+    int height = frame->height;
+
+    av_assert0(frame && frame->data[0] && output_file);
+
+    for (idx = 0; idx < height; idx++) {
+        if ((size = fwrite(frame->data[0] + idx*frame->linesize[0],
+                           1, width, output_file)) < 0) {
+                fprintf(stderr, "Dump Y to file error.\n");
+                return -1;
+        }
+    }
+
+    height >>= 1;
+    for (idx = 0; idx < height; idx++) {
+        if ((size = fwrite(frame->data[1] + idx*frame->linesize[1],
+                           1, width, output_file)) < 0) {
+            fprintf(stderr, "Dump UV to file error.\n");
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+int decode_write(AVCodecContext *avctx, AVPacket packet, int flush)
+{
+    AVFrame *frame = NULL;
+    int ret = 0, got_frame = 0;
+
+    if (!(frame = av_frame_alloc()))
+        return AVERROR(ENOMEM);
+
+    if ((ret = avcodec_decode_video2(avctx, frame, &got_frame, &packet)) < 0) {
+        fprintf(stderr, "Error during decoding\n");
+        goto fail;
+    }
+
+    if (got_frame) {
+        if (AV_PIX_FMT_VAAPI == frame->format) {
+            /* retrieve data from GPU to CPU */
+            if ((ret = retrieve_data(frame)) < 0)
+                goto fail;
+
+            if ((ret = write_frame(frame)) < 0)
+                goto fail;
+        }
+    } else if (flush == 1) {
+            ret = -1;
+    }
+
+fail:
+    av_frame_free(&frame);
+    return ret;
+}
+
+/* flush the decoder */
+int flush(AVCodecContext *avctx)
+{
+    AVPacket packet;
+    int ret = 0;
+
+    av_init_packet(&packet);
+    packet.data = NULL;
+    packet.size = 0;
+
+    while (1) {
+        if ((ret = decode_write(avctx, packet, 1)) < 0)
+            break;
+    }
+    av_packet_unref(&packet);
+
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    AVFormatContext *input_ctx = NULL;
+    int i,video_stream,ret;
+    AVCodecContext *decoder_ctx = NULL;
+    AVCodec *decoder = NULL;
+    AVPacket packet;
+
+    if (argc < 3) {
+        fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]);
+        return -1;
+    }
+
+    av_register_all();
+
+    /* open the input file */
+    if (avformat_open_input(&input_ctx, argv[1], NULL, NULL) != 0) {
+        fprintf(stderr, "Cannot open input file '%s'\n", argv[1]);
+        return -1;
+    }
+
+    if (avformat_find_stream_info(input_ctx, NULL) < 0) {
+        fprintf(stderr, "Couldn't find input stream information.\n");
+        return -1;
+    }
+
+    /* find the video stream information */
+    video_stream = -1;
+    for (i = 0; i < input_ctx->nb_streams; i++) {
+        AVStream *st = input_ctx->streams[i];
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+            /* NOTE: just handle the first video stream */
+            video_stream = i;
+            break;
+        }
+    }
+
+    if (video_stream == -1) {
+        fprintf(stderr, "No find a video stream in the input file.\n");
+        return -1;
+    }
+
+    /* initialize the video decoder */
+    if (!(decoder = 
avcodec_find_decoder(input_ctx->streams[video_stream]->codecpar->codec_id))) {
+        fprintf(stderr, "Could not find input codec\n");
+        avformat_close_input(&input_ctx);
+        return -1;
+    }
+
+    if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
+        return AVERROR(ENOMEM);
+
+    if (avcodec_parameters_to_context(decoder_ctx,
+                                      
input_ctx->streams[video_stream]->codecpar) < 0) {
+        avcodec_free_context(&decoder_ctx);
+        avformat_close_input(&input_ctx);
+        return -1;
+    }
+
+    decoder_ctx->get_format  = get_hw_vaapi_format;
+    decoder_ctx->get_buffer2 = get_hw_vaapi_buffer;
+    av_opt_set_int(decoder_ctx, "refcounted_frames", 1, 0);
+
+    if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
+        fprintf(stderr, "Failed to open codec for stream #%u\n", i);
+        return ret;
+    }
+
+    /* open the output file to dump YUV */
+    output_file = fopen(argv[2], "w+");
+
+    /* actual decoding and dump the YUV data */
+    while (av_read_frame(input_ctx, &packet) >= 0) {
+        if (video_stream == packet.stream_index)
+                ret = decode_write(decoder_ctx, packet, 0);
+        av_packet_unref(&packet);
+
+        if (ret < 0)
+                break;
+    }
+
+    /* flush the decoder */
+    flush(decoder_ctx);
+
+    if (output_file)
+        fclose(output_file);
+    avcodec_free_context(&decoder_ctx);
+    avformat_close_input(&input_ctx);
+
+    av_buffer_unref(&frames_ref);
+    av_buffer_unref(&device_ref);
+
+    return ret;
+}
+
-- 
2.9.3

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