[FFmpeg-devel,2/2] example/vaapi_transcode: Add a VA-API transcode example.

Submitted by Jun Zhao on Jan. 11, 2018, 7:07 a.m.

Details

Message ID 2fd1530e-43db-37f5-562d-18b3bcb420df@gmail.com
State New
Headers show

Commit Message

Jun Zhao Jan. 11, 2018, 7:07 a.m.
From b76a2f790814df326d7d93c54b14b3c8e74ab759 Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.zhao@intel.com>
Date: Thu, 11 Jan 2018 15:00:30 +0800
Subject: [PATCH 2/2] example/vaapi_transcode: Add a VA-API transcode example.

Add VA-API transcoding example, useage like:
./vaapi_transcode input_stream h264_vaapi output_stream

Signed-off-by: Jun Zhao <jun.zhao@intel.com>
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>
---
 configure                      |   2 +
 doc/examples/Makefile          |   1 +
 doc/examples/vaapi_transcode.c | 256 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 259 insertions(+)
 create mode 100644 doc/examples/vaapi_transcode.c

Comments

Mark Thompson Jan. 19, 2018, 1:45 a.m.
On 11/01/18 07:07, Jun Zhao wrote:
> From b76a2f790814df326d7d93c54b14b3c8e74ab759 Mon Sep 17 00:00:00 2001
> From: Jun Zhao <jun.zhao@intel.com>
> Date: Thu, 11 Jan 2018 15:00:30 +0800
> Subject: [PATCH 2/2] example/vaapi_transcode: Add a VA-API transcode example.
> 
> Add VA-API transcoding example, useage like:
> ./vaapi_transcode input_stream h264_vaapi output_stream
> 
> Signed-off-by: Jun Zhao <jun.zhao@intel.com>
> Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>
> ---
>  configure                      |   2 +
>  doc/examples/Makefile          |   1 +
>  doc/examples/vaapi_transcode.c | 256 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 259 insertions(+)
>  create mode 100644 doc/examples/vaapi_transcode.c
> 
> diff --git a/configure b/configure
> index b8985ba542..6d08c0fbbb 100755
> --- a/configure
> +++ b/configure
> @@ -1526,6 +1526,7 @@ EXAMPLE_LIST="
>      transcode_aac_example
>      transcoding_example
>      vaapi_encode_example
> +    vaapi_transcode_example
>  "
>  
>  EXTERNAL_AUTODETECT_LIBRARY_LIST="
> @@ -3319,6 +3320,7 @@ scaling_video_example_deps="avutil swscale"
>  transcode_aac_example_deps="avcodec avformat swresample"
>  transcoding_example_deps="avfilter avcodec avformat avutil"
>  vaapi_encode_example_deps="avcodec avutil"
> +vaapi_transcode_example_deps="avcodec avformat avutil"
>  
>  # EXTRALIBS_LIST
>  cpu_init_extralibs="pthreads_extralibs"
> diff --git a/doc/examples/Makefile b/doc/examples/Makefile
> index da5af36532..928ff306b3 100644
> --- a/doc/examples/Makefile
> +++ b/doc/examples/Makefile
> @@ -20,6 +20,7 @@ EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE)     += scaling_video
>  EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE)     += transcode_aac
>  EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE)       += transcoding
>  EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE)      += vaapi_encode
> +EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE)   += vaapi_transcode
>  
>  EXAMPLES       := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)$(EXESUF))
>  EXAMPLES_G     := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)_g$(EXESUF))
> diff --git a/doc/examples/vaapi_transcode.c b/doc/examples/vaapi_transcode.c
> new file mode 100644
> index 0000000000..b92a387f2f
> --- /dev/null
> +++ b/doc/examples/vaapi_transcode.c
> @@ -0,0 +1,256 @@
> +/*
> + * Video Acceleration API (video transcoding) transcode 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 transcoding example.
> + *
> + * @example vaapi_transcode.c
> + * This example shows how to do VAAPI-accelerated transcoding.
> + * Usage: vaapi_transcode input_stream h264_vaapi output_stream
> + */
> +
> +#include <stdio.h>
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +#include <libavutil/hwcontext.h>
> +#include <libavutil/avassert.h>
> +#include <errno.h>
> +
> +static AVFormatContext *ifmt_ctx = NULL;
> +static AVBufferRef *hw_device_ctx = NULL;
> +static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
> +static int video_stream = -1;
> +static FILE *fout;
> +static int initialized = 0;
> +
> +static enum AVPixelFormat get_vaapi_format(AVCodecContext *ctx,
> +                                           const enum AVPixelFormat *pix_fmts)
> +{
> +    const enum AVPixelFormat *p;
> +
> +    for (p = pix_fmts; *p != -1; p++) {

AV_PIX_FMT_NONE would be clearer than -1 here.

> +        if (*p == AV_PIX_FMT_VAAPI)
> +            return *p;
> +    }
> +
> +    fprintf(stderr, "Failed to get vaapi pix format\n");

Maybe something like "Unable to decode this file using VAAPI", since that's what it actually means (the decoder didn't offer the VAAPI output format).

> +    return AV_PIX_FMT_NONE;
> +}
> +
> +static int open_input_file(const char *filename)
> +{
> +    int ret;
> +    AVCodec *decoder = NULL;
> +    AVStream *video = NULL;
> +
> +    if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
> +        fprintf(stderr, "Cannot open input file '%s', Error code: %s\n",
> +                filename, av_err2str(ret));
> +        return ret;
> +    }
> +
> +    if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
> +        fprintf(stderr, "Cannot find input stream information. Error code: %s\n",
> +                av_err2str(ret));
> +        return ret;
> +    }
> +
> +    ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
> +    if (ret < 0) {
> +        fprintf(stderr, "Cannot find a video stream in the input file.\
> +                Error code: %s\n", av_err2str(ret));

Use multiple string constants ("foo" "bar") rather than continuation escapes - this is putting a lot of spaces in the middle of the message.

> +        return ret;
> +    }
> +    video_stream = ret;
> +
> +    if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
> +        return AVERROR(ENOMEM);
> +
> +    video = ifmt_ctx->streams[video_stream];
> +    if ((ret = avcodec_parameters_to_context(decoder_ctx, video->codecpar)) < 0) {
> +        fprintf(stderr, "avcodec_parameters_to_context error. Error code: %s\n",
> +                av_err2str(ret));
> +        return ret;
> +    }
> +
> +    decoder_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
> +    decoder_ctx->get_format    = get_vaapi_format;
> +
> +    if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0)
> +        fprintf(stderr, "Failed to open codec for decoding. Error code: %s\n",
> +                av_err2str(ret));
> +
> +    return ret;
> +}
> +
> +static int encode_write(AVFrame *frame)
> +{
> +    int ret = 0;
> +    AVPacket enc_pkt;
> +
> +    av_init_packet(&enc_pkt);
> +    enc_pkt.data = NULL;
> +    enc_pkt.size = 0;
> +
> +    if ((ret = avcodec_send_frame(encoder_ctx, frame)) < 0) {
> +        fprintf(stderr, "Error during encoding. Error code: %s\n", av_err2str(ret));
> +        goto end;
> +    }
> +    while (1) {
> +        ret = avcodec_receive_packet(encoder_ctx, &enc_pkt);
> +        if (ret)
> +            break;
> +
> +        enc_pkt.stream_index = 0;
> +        ret = fwrite(enc_pkt.data, 1, enc_pkt.size, fout);

fwrite() can fail (returning zero).

> +    }
> +
> +end:
> +    if (ret == AVERROR_EOF)
> +        return 0;
> +    ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
> +    return ret;
> +}
> +
> +static int dec_enc(AVPacket *pkt, AVCodec *enc_codec)
> +{
> +    AVFrame *frame;
> +    int ret = 0;
> +
> +    ret = avcodec_send_packet(decoder_ctx, pkt);
> +    if (ret < 0) {
> +        fprintf(stderr, "Error during decoding. Error code: %s\n", av_err2str(ret));
> +        return ret;
> +    }
> +
> +    while (ret >= 0) {
> +        if (!(frame = av_frame_alloc()))
> +            return AVERROR(ENOMEM);
> +
> +        ret = avcodec_receive_frame(decoder_ctx, frame);
> +        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
> +            av_frame_free(&frame);
> +            return 0;
> +        } else if (ret < 0) {
> +            fprintf(stderr, "Error while decoding. Error code: %s\n", av_err2str(ret));
> +            goto fail;
> +        }
> +
> +        if (!initialized) {
> +            /* Here we need to ref hw_frames_ctx of decoder to initialize encoder's codec.
> +               Only after we get a decoded frame, can we obtain its hw_frames_ctx */
> +            encoder_ctx->hw_frames_ctx = av_buffer_ref(decoder_ctx->hw_frames_ctx);
> +            if (!encoder_ctx->hw_frames_ctx) {
> +                ret = AVERROR(ENOMEM);
> +                goto fail;
> +            }
> +            if ((ret = avcodec_open2(encoder_ctx, enc_codec, NULL)) < 0) {
> +                fprintf(stderr, "Error while open encode codec. Error code: %s\n",
> +                        av_err2str(ret));
> +                goto fail;
> +            }
> +            initialized = 1;
> +        }
> +
> +        if ((ret = encode_write(frame)) < 0)
> +            fprintf(stderr, "Error during encoding and writing.\n");
> +
> +fail:
> +        av_frame_free(&frame);
> +        if (ret < 0)
> +            return ret;
> +    }
> +    return 0;
> +}
> +
> +int main(int argc, char **argv) {
> +    int ret = 0;
> +    AVPacket dec_pkt;
> +    AVCodec *enc_codec;
> +
> +    if (argc != 4) {
> +        fprintf(stderr, "Usage: %s <input file> <encode codec> <output file>\n", argv[0]);
> +        return -1;
> +    }
> +
> +    av_register_all();
> +
> +    ret = av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, NULL, NULL, 0);
> +    if (ret < 0) {
> +        fprintf(stderr, "Failed to create a VAAPI device. Error code: %s\n", av_err2str(ret));
> +        return -1;
> +    }
> +
> +    if ((ret = open_input_file(argv[1])) < 0)
> +        goto end;
> +
> +    if (!(enc_codec = avcodec_find_encoder_by_name(argv[2]))) {
> +        fprintf(stderr, "Could not find encoder '%s'\n", argv[2]);
> +        ret = -1;
> +        goto end;
> +    }
> +
> +    if (!(fout = fopen(argv[3], "w+b"))) {
> +        fprintf(stderr, "Failed to open output file: %s\n", strerror(errno));
> +        ret = -1;
> +        goto end;
> +    }
> +
> +    if (!(encoder_ctx= avcodec_alloc_context3(enc_codec))) {
> +        ret = AVERROR(ENOMEM);
> +        goto end;
> +    }
> +
> +    /* set AVCodecContext Parameters */
> +    encoder_ctx->width     = decoder_ctx->width;
> +    encoder_ctx->height    = decoder_ctx->height;

Not sure you necessarily know this width and height here before the decoder has produced any output?  libavformat may have filled this in some cases, but I don't think it has to in all.

> +    encoder_ctx->time_base = (AVRational){1, 25};
> +    encoder_ctx->pix_fmt   = AV_PIX_FMT_VAAPI;
> +
> +    /* read all packets and only transcoding video */
> +    while (ret >= 0) {
> +        if ((ret = av_read_frame(ifmt_ctx, &dec_pkt)) < 0)
> +            break;
> +
> +        if (video_stream == dec_pkt.stream_index)
> +            ret = dec_enc(&dec_pkt, enc_codec);
> +
> +        av_packet_unref(&dec_pkt);
> +    }
> +
> +    /* flush decoder */
> +    dec_pkt.data = NULL;
> +    dec_pkt.size = 0;
> +    ret = dec_enc(&dec_pkt, enc_codec);
> +    av_packet_unref(&dec_pkt);
> +
> +    /* flush encoder */
> +    ret = encode_write(NULL);
> +
> +end:
> +    avformat_close_input(&ifmt_ctx);
> +    if (fout)
> +        fclose(fout);
> +    avcodec_free_context(&decoder_ctx);
> +    avcodec_free_context(&encoder_ctx);
> +    av_buffer_unref(&hw_device_ctx);
> +    return ret;
> +}
> -- 
> 2.14.1
> 

Generally looks fine, and tested a bit.

Probably ignorable, but I note it doesn't produce a usable stream for VP8/VP9 because they don't support raw streams like this.

Thanks,

- Mark

Patch hide | download patch | download mbox

diff --git a/configure b/configure
index b8985ba542..6d08c0fbbb 100755
--- a/configure
+++ b/configure
@@ -1526,6 +1526,7 @@  EXAMPLE_LIST="
     transcode_aac_example
     transcoding_example
     vaapi_encode_example
+    vaapi_transcode_example
 "
 
 EXTERNAL_AUTODETECT_LIBRARY_LIST="
@@ -3319,6 +3320,7 @@  scaling_video_example_deps="avutil swscale"
 transcode_aac_example_deps="avcodec avformat swresample"
 transcoding_example_deps="avfilter avcodec avformat avutil"
 vaapi_encode_example_deps="avcodec avutil"
+vaapi_transcode_example_deps="avcodec avformat avutil"
 
 # EXTRALIBS_LIST
 cpu_init_extralibs="pthreads_extralibs"
diff --git a/doc/examples/Makefile b/doc/examples/Makefile
index da5af36532..928ff306b3 100644
--- a/doc/examples/Makefile
+++ b/doc/examples/Makefile
@@ -20,6 +20,7 @@  EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE)     += scaling_video
 EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE)     += transcode_aac
 EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE)       += transcoding
 EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE)      += vaapi_encode
+EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE)   += vaapi_transcode
 
 EXAMPLES       := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)$(EXESUF))
 EXAMPLES_G     := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)_g$(EXESUF))
diff --git a/doc/examples/vaapi_transcode.c b/doc/examples/vaapi_transcode.c
new file mode 100644
index 0000000000..b92a387f2f
--- /dev/null
+++ b/doc/examples/vaapi_transcode.c
@@ -0,0 +1,256 @@ 
+/*
+ * Video Acceleration API (video transcoding) transcode 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 transcoding example.
+ *
+ * @example vaapi_transcode.c
+ * This example shows how to do VAAPI-accelerated transcoding.
+ * Usage: vaapi_transcode input_stream h264_vaapi output_stream
+ */
+
+#include <stdio.h>
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+#include <libavutil/hwcontext.h>
+#include <libavutil/avassert.h>
+#include <errno.h>
+
+static AVFormatContext *ifmt_ctx = NULL;
+static AVBufferRef *hw_device_ctx = NULL;
+static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
+static int video_stream = -1;
+static FILE *fout;
+static int initialized = 0;
+
+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;
+    }
+
+    fprintf(stderr, "Failed to get vaapi pix format\n");
+    return AV_PIX_FMT_NONE;
+}
+
+static int open_input_file(const char *filename)
+{
+    int ret;
+    AVCodec *decoder = NULL;
+    AVStream *video = NULL;
+
+    if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
+        fprintf(stderr, "Cannot open input file '%s', Error code: %s\n",
+                filename, av_err2str(ret));
+        return ret;
+    }
+
+    if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
+        fprintf(stderr, "Cannot find input stream information. Error code: %s\n",
+                av_err2str(ret));
+        return ret;
+    }
+
+    ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
+    if (ret < 0) {
+        fprintf(stderr, "Cannot find a video stream in the input file.\
+                Error code: %s\n", av_err2str(ret));
+        return ret;
+    }
+    video_stream = ret;
+
+    if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
+        return AVERROR(ENOMEM);
+
+    video = ifmt_ctx->streams[video_stream];
+    if ((ret = avcodec_parameters_to_context(decoder_ctx, video->codecpar)) < 0) {
+        fprintf(stderr, "avcodec_parameters_to_context error. Error code: %s\n",
+                av_err2str(ret));
+        return ret;
+    }
+
+    decoder_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
+    decoder_ctx->get_format    = get_vaapi_format;
+
+    if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0)
+        fprintf(stderr, "Failed to open codec for decoding. Error code: %s\n",
+                av_err2str(ret));
+
+    return ret;
+}
+
+static int encode_write(AVFrame *frame)
+{
+    int ret = 0;
+    AVPacket enc_pkt;
+
+    av_init_packet(&enc_pkt);
+    enc_pkt.data = NULL;
+    enc_pkt.size = 0;
+
+    if ((ret = avcodec_send_frame(encoder_ctx, frame)) < 0) {
+        fprintf(stderr, "Error during encoding. Error code: %s\n", av_err2str(ret));
+        goto end;
+    }
+    while (1) {
+        ret = avcodec_receive_packet(encoder_ctx, &enc_pkt);
+        if (ret)
+            break;
+
+        enc_pkt.stream_index = 0;
+        ret = fwrite(enc_pkt.data, 1, enc_pkt.size, fout);
+    }
+
+end:
+    if (ret == AVERROR_EOF)
+        return 0;
+    ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
+    return ret;
+}
+
+static int dec_enc(AVPacket *pkt, AVCodec *enc_codec)
+{
+    AVFrame *frame;
+    int ret = 0;
+
+    ret = avcodec_send_packet(decoder_ctx, pkt);
+    if (ret < 0) {
+        fprintf(stderr, "Error during decoding. Error code: %s\n", av_err2str(ret));
+        return ret;
+    }
+
+    while (ret >= 0) {
+        if (!(frame = av_frame_alloc()))
+            return AVERROR(ENOMEM);
+
+        ret = avcodec_receive_frame(decoder_ctx, frame);
+        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
+            av_frame_free(&frame);
+            return 0;
+        } else if (ret < 0) {
+            fprintf(stderr, "Error while decoding. Error code: %s\n", av_err2str(ret));
+            goto fail;
+        }
+
+        if (!initialized) {
+            /* Here we need to ref hw_frames_ctx of decoder to initialize encoder's codec.
+               Only after we get a decoded frame, can we obtain its hw_frames_ctx */
+            encoder_ctx->hw_frames_ctx = av_buffer_ref(decoder_ctx->hw_frames_ctx);
+            if (!encoder_ctx->hw_frames_ctx) {
+                ret = AVERROR(ENOMEM);
+                goto fail;
+            }
+            if ((ret = avcodec_open2(encoder_ctx, enc_codec, NULL)) < 0) {
+                fprintf(stderr, "Error while open encode codec. Error code: %s\n",
+                        av_err2str(ret));
+                goto fail;
+            }
+            initialized = 1;
+        }
+
+        if ((ret = encode_write(frame)) < 0)
+            fprintf(stderr, "Error during encoding and writing.\n");
+
+fail:
+        av_frame_free(&frame);
+        if (ret < 0)
+            return ret;
+    }
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    int ret = 0;
+    AVPacket dec_pkt;
+    AVCodec *enc_codec;
+
+    if (argc != 4) {
+        fprintf(stderr, "Usage: %s <input file> <encode codec> <output file>\n", argv[0]);
+        return -1;
+    }
+
+    av_register_all();
+
+    ret = av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, NULL, NULL, 0);
+    if (ret < 0) {
+        fprintf(stderr, "Failed to create a VAAPI device. Error code: %s\n", av_err2str(ret));
+        return -1;
+    }
+
+    if ((ret = open_input_file(argv[1])) < 0)
+        goto end;
+
+    if (!(enc_codec = avcodec_find_encoder_by_name(argv[2]))) {
+        fprintf(stderr, "Could not find encoder '%s'\n", argv[2]);
+        ret = -1;
+        goto end;
+    }
+
+    if (!(fout = fopen(argv[3], "w+b"))) {
+        fprintf(stderr, "Failed to open output file: %s\n", strerror(errno));
+        ret = -1;
+        goto end;
+    }
+
+    if (!(encoder_ctx= avcodec_alloc_context3(enc_codec))) {
+        ret = AVERROR(ENOMEM);
+        goto end;
+    }
+
+    /* set AVCodecContext Parameters */
+    encoder_ctx->width     = decoder_ctx->width;
+    encoder_ctx->height    = decoder_ctx->height;
+    encoder_ctx->time_base = (AVRational){1, 25};
+    encoder_ctx->pix_fmt   = AV_PIX_FMT_VAAPI;
+
+    /* read all packets and only transcoding video */
+    while (ret >= 0) {
+        if ((ret = av_read_frame(ifmt_ctx, &dec_pkt)) < 0)
+            break;
+
+        if (video_stream == dec_pkt.stream_index)
+            ret = dec_enc(&dec_pkt, enc_codec);
+
+        av_packet_unref(&dec_pkt);
+    }
+
+    /* flush decoder */
+    dec_pkt.data = NULL;
+    dec_pkt.size = 0;
+    ret = dec_enc(&dec_pkt, enc_codec);
+    av_packet_unref(&dec_pkt);
+
+    /* flush encoder */
+    ret = encode_write(NULL);
+
+end:
+    avformat_close_input(&ifmt_ctx);
+    if (fout)
+        fclose(fout);
+    avcodec_free_context(&decoder_ctx);
+    avcodec_free_context(&encoder_ctx);
+    av_buffer_unref(&hw_device_ctx);
+    return ret;
+}