[FFmpeg-devel] [PATCH V2] examples/vaapi_dec: Add a VA-API hwaccel decoding example

Jun Zhao mypopydev at gmail.com
Tue Jul 11 07:06:10 EEST 2017


V2: re-work with new hw decoding API.
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From 0e4d230ae4c98949a962c6bbdad31d216b54bb6a Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.zhao at intel.com>
Date: Tue, 21 Mar 2017 11:04:41 +0800
Subject: [V2] examples/vaapi_dec: Add a VA-API hwaccel decoding example.

Add a VA-API hwaccel decoding example.

Signed-off-by: Liu, Kaixuan <kaixuan.liu at intel.com>
Signed-off-by: Jun Zhao <jun.zhao at intel.com>
---
 doc/examples/vaapi_dec.c | 266 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 266 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 0000000000..01320a3b71
--- /dev/null
+++ b/doc/examples/vaapi_dec.c
@@ -0,0 +1,266 @@
+/*
+ * 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 <libavutil/pixdesc.h>
+#include <libavutil/hwcontext.h>
+#include <libavutil/opt.h>
+#include <libavutil/hwcontext_vaapi.h>
+#include <libavutil/avassert.h>
+
+static AVBufferRef *hw_device_ctx = NULL;
+FILE *output_file = NULL;
+
+int decoder_init_vaapi(AVCodecContext *ctx)
+{
+    int err = 0;
+    const char *dev_name = "/dev/dri/renderD128";
+
+    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;
+    }
+    ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
+
+    return err;
+}
+
+static enum AVPixelFormat get_vaapi_format(AVCodecContext *ctx,
+                                           const enum AVPixelFormat *pix_fmts)
+{
+    const enum AVPixelFormat *p;
+
+    for (p = pix_fmts; *p != -1; p++) {
+        if (*p == AV_PIX_FMT_VAAPI)
+            return *p;
+    }
+
+    return AV_PIX_FMT_NONE;
+}
+
+int retrieve_data(AVFrame *input)
+{
+    AVFrame *output = NULL;
+    int err;
+    av_assert0(input->format == AV_PIX_FMT_VAAPI);
+
+    if (!(output = av_frame_alloc()))
+        return AVERROR(ENOMEM);
+    /* default output nv12 */
+    output->format = AV_PIX_FMT_NV12;
+    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;
+
+    ret = avcodec_send_packet(avctx, &packet);
+    if (ret < 0 && ret != AVERROR_EOF)
+        return 0;
+
+    if (!(frame = av_frame_alloc()))
+        return AVERROR(ENOMEM);
+
+    ret = avcodec_receive_frame(avctx, frame);
+    if (ret >= 0) {
+        /* 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 == 0) {
+        ret = 0;
+    }
+
+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");
+        goto fail;
+    }
+
+    /* 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) {
+            video_stream = i;        /* NOTE: just handle the first video stream */
+            break;
+        }
+    }
+
+    if (video_stream == -1) {
+        fprintf(stderr, "No find a video stream in the input file.\n");
+        goto fail;
+    }
+
+    /* 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");
+        goto fail;
+    }
+
+    if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
+        return AVERROR(ENOMEM);
+
+    if (avcodec_parameters_to_context(decoder_ctx,
+                                      input_ctx->streams[video_stream]->codecpar) < 0)
+        goto fail;
+
+    decoder_ctx->get_format  = get_vaapi_format;
+    av_opt_set_int(decoder_ctx, "refcounted_frames", 1, 0);
+
+    if (decoder_init_vaapi(decoder_ctx) < 0)
+        goto fail;
+
+    if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
+        fprintf(stderr, "Failed to open codec for stream #%u\n", i);
+        goto fail;
+    }
+
+    /* 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);
+
+fail:
+    if (output_file)
+        fclose(output_file);
+    avcodec_free_context(&decoder_ctx);
+    avformat_close_input(&input_ctx);
+    av_buffer_unref(&hw_device_ctx);
+
+    return ret;
+}
-- 
2.11.0



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