diff mbox series

[FFmpeg-devel,v3,1/2] avfilter/dnn/dnn_backend_tf: simplify the code with ff_hex_to_data

Message ID 1619606829-25051-1-git-send-email-lance.lmwang@gmail.com
State Accepted
Commit f183d6555e714e00b41aec728feb8a731826cbdc
Headers show
Series [FFmpeg-devel,v3,1/2] avfilter/dnn/dnn_backend_tf: simplify the code with ff_hex_to_data | expand

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Commit Message

Limin Wang April 28, 2021, 10:47 a.m. UTC
From: Limin Wang <lance.lmwang@gmail.com>

please use tools/python/tf_sess_config.py to get the sess_config after that.
note the byte order of session config is in normal order.
bump the MICRO version for the config change.

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
---
 libavfilter/dnn/dnn_backend_tf.c | 42 +++++++------------------------------
 libavfilter/version.h            |  2 +-
 tools/python/tf_sess_config.py   | 45 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 35 deletions(-)
 create mode 100644 tools/python/tf_sess_config.py

Comments

Guo, Yejun April 28, 2021, 12:26 p.m. UTC | #1
> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> lance.lmwang@gmail.com
> Sent: 2021年4月28日 18:47
> To: ffmpeg-devel@ffmpeg.org
> Cc: Limin Wang <lance.lmwang@gmail.com>
> Subject: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> simplify the code with ff_hex_to_data
> 
> From: Limin Wang <lance.lmwang@gmail.com>
> 
> please use tools/python/tf_sess_config.py to get the sess_config after that.
> note the byte order of session config is in normal order.
> bump the MICRO version for the config change.
> 
> Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> ---
>  libavfilter/dnn/dnn_backend_tf.c | 42 +++++++------------------------------
>  libavfilter/version.h            |  2 +-
>  tools/python/tf_sess_config.py   | 45
> ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 54 insertions(+), 35 deletions(-)
>  create mode 100644 tools/python/tf_sess_config.py
> 
> diff --git a/libavfilter/dnn/dnn_backend_tf.c
> b/libavfilter/dnn/dnn_backend_tf.c
> index fb799d2..076dd3d 100644
> --- a/libavfilter/dnn/dnn_backend_tf.c
> +++ b/libavfilter/dnn/dnn_backend_tf.c
> @@ -28,6 +28,7 @@
>  #include "dnn_backend_native_layer_conv2d.h"
>  #include "dnn_backend_native_layer_depth2space.h"
>  #include "libavformat/avio.h"
> +#include "libavformat/internal.h"
>  #include "libavutil/avassert.h"
>  #include "../internal.h"
>  #include "dnn_backend_native_layer_pad.h"
> @@ -206,53 +207,26 @@ static DNNReturnType load_tf_model(TFModel
> *tf_model, const char *model_filename
> 
>      // prepare the sess config data
>      if (tf_model->ctx.options.sess_config != NULL) {
> +        const char *config;
>          /*
>          tf_model->ctx.options.sess_config is hex to present the serialized
> proto
>          required by TF_SetConfig below, so we need to first generate the
> serialized
> -        proto in a python script, the following is a script example to
> generate
> -        serialized proto which specifies one GPU, we can change the script
> to add
> -        more options.
> -
> -        import tensorflow as tf
> -        gpu_options = tf.GPUOptions(visible_device_list='0')
> -        config = tf.ConfigProto(gpu_options=gpu_options)
> -        s = config.SerializeToString()
> -        b = ''.join("%02x" % int(ord(b)) for b in s[::-1])
> -        print('0x%s' % b)
> -
> -        the script output looks like: 0xab...cd, and then pass 0xab...cd to
> sess_config.
> +        proto in a python script, tools/python/tf_sess_config.py is a script
> example
> +        to generate the configs of sess_config.
>          */
> -        char tmp[3];
> -        tmp[2] = '\0';
> -
>          if (strncmp(tf_model->ctx.options.sess_config, "0x", 2) != 0) {
>              av_log(ctx, AV_LOG_ERROR, "sess_config should start with
> '0x'\n");
>              return DNN_ERROR;
>          }
> +        config = tf_model->ctx.options.sess_config + 2;
> +        sess_config_length = ff_hex_to_data(NULL, config);
> 
> -        sess_config_length = strlen(tf_model->ctx.options.sess_config);
> -        if (sess_config_length % 2 != 0) {
> -            av_log(ctx, AV_LOG_ERROR, "the length of sess_config is not
> even (%s), "
> -                                      "please re-generate the
> config.\n",
> -
> tf_model->ctx.options.sess_config);
> -            return DNN_ERROR;
> -        }
> -
> -        sess_config_length -= 2; //ignore the first '0x'
> -        sess_config_length /= 2; //get the data length in byte
> -
> -        sess_config = av_malloc(sess_config_length);
> +        sess_config = av_mallocz(sess_config_length +
> AV_INPUT_BUFFER_PADDING_SIZE);

just get a concern, why we need to add PADDING_SIZE here.
Will there be potential issue if not add?

>          if (!sess_config) {
>              av_log(ctx, AV_LOG_ERROR, "failed to allocate memory\n");
>              return DNN_ERROR;
>          }
> -
> -        for (int i = 0; i < sess_config_length; i++) {
> -            int index = 2 + (sess_config_length - 1 - i) * 2;
> -            tmp[0] = tf_model->ctx.options.sess_config[index];
> -            tmp[1] = tf_model->ctx.options.sess_config[index + 1];
> -            sess_config[i] = strtol(tmp, NULL, 16);
> -        }
> +        ff_hex_to_data(sess_config, config);
>      }
>
Limin Wang April 28, 2021, 1:17 p.m. UTC | #2
On Wed, Apr 28, 2021 at 12:26:54PM +0000, Guo, Yejun wrote:
> 
> 
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> > lance.lmwang@gmail.com
> > Sent: 2021年4月28日 18:47
> > To: ffmpeg-devel@ffmpeg.org
> > Cc: Limin Wang <lance.lmwang@gmail.com>
> > Subject: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> > simplify the code with ff_hex_to_data
> > 
> > From: Limin Wang <lance.lmwang@gmail.com>
> > 
> > please use tools/python/tf_sess_config.py to get the sess_config after that.
> > note the byte order of session config is in normal order.
> > bump the MICRO version for the config change.
> > 
> > Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> > ---
> >  libavfilter/dnn/dnn_backend_tf.c | 42 +++++++------------------------------
> >  libavfilter/version.h            |  2 +-
> >  tools/python/tf_sess_config.py   | 45
> > ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 54 insertions(+), 35 deletions(-)
> >  create mode 100644 tools/python/tf_sess_config.py
> > 
> > diff --git a/libavfilter/dnn/dnn_backend_tf.c
> > b/libavfilter/dnn/dnn_backend_tf.c
> > index fb799d2..076dd3d 100644
> > --- a/libavfilter/dnn/dnn_backend_tf.c
> > +++ b/libavfilter/dnn/dnn_backend_tf.c
> > @@ -28,6 +28,7 @@
> >  #include "dnn_backend_native_layer_conv2d.h"
> >  #include "dnn_backend_native_layer_depth2space.h"
> >  #include "libavformat/avio.h"
> > +#include "libavformat/internal.h"
> >  #include "libavutil/avassert.h"
> >  #include "../internal.h"
> >  #include "dnn_backend_native_layer_pad.h"
> > @@ -206,53 +207,26 @@ static DNNReturnType load_tf_model(TFModel
> > *tf_model, const char *model_filename
> > 
> >      // prepare the sess config data
> >      if (tf_model->ctx.options.sess_config != NULL) {
> > +        const char *config;
> >          /*
> >          tf_model->ctx.options.sess_config is hex to present the serialized
> > proto
> >          required by TF_SetConfig below, so we need to first generate the
> > serialized
> > -        proto in a python script, the following is a script example to
> > generate
> > -        serialized proto which specifies one GPU, we can change the script
> > to add
> > -        more options.
> > -
> > -        import tensorflow as tf
> > -        gpu_options = tf.GPUOptions(visible_device_list='0')
> > -        config = tf.ConfigProto(gpu_options=gpu_options)
> > -        s = config.SerializeToString()
> > -        b = ''.join("%02x" % int(ord(b)) for b in s[::-1])
> > -        print('0x%s' % b)
> > -
> > -        the script output looks like: 0xab...cd, and then pass 0xab...cd to
> > sess_config.
> > +        proto in a python script, tools/python/tf_sess_config.py is a script
> > example
> > +        to generate the configs of sess_config.
> >          */
> > -        char tmp[3];
> > -        tmp[2] = '\0';
> > -
> >          if (strncmp(tf_model->ctx.options.sess_config, "0x", 2) != 0) {
> >              av_log(ctx, AV_LOG_ERROR, "sess_config should start with
> > '0x'\n");
> >              return DNN_ERROR;
> >          }
> > +        config = tf_model->ctx.options.sess_config + 2;
> > +        sess_config_length = ff_hex_to_data(NULL, config);
> > 
> > -        sess_config_length = strlen(tf_model->ctx.options.sess_config);
> > -        if (sess_config_length % 2 != 0) {
> > -            av_log(ctx, AV_LOG_ERROR, "the length of sess_config is not
> > even (%s), "
> > -                                      "please re-generate the
> > config.\n",
> > -
> > tf_model->ctx.options.sess_config);
> > -            return DNN_ERROR;
> > -        }
> > -
> > -        sess_config_length -= 2; //ignore the first '0x'
> > -        sess_config_length /= 2; //get the data length in byte
> > -
> > -        sess_config = av_malloc(sess_config_length);
> > +        sess_config = av_mallocz(sess_config_length +
> > AV_INPUT_BUFFER_PADDING_SIZE);
> 
> just get a concern, why we need to add PADDING_SIZE here.
> Will there be potential issue if not add?

I just want to make sure it's safe even if the sess_config_length is zero.



> 
> >          if (!sess_config) {
> >              av_log(ctx, AV_LOG_ERROR, "failed to allocate memory\n");
> >              return DNN_ERROR;
> >          }
> > -
> > -        for (int i = 0; i < sess_config_length; i++) {
> > -            int index = 2 + (sess_config_length - 1 - i) * 2;
> > -            tmp[0] = tf_model->ctx.options.sess_config[index];
> > -            tmp[1] = tf_model->ctx.options.sess_config[index + 1];
> > -            sess_config[i] = strtol(tmp, NULL, 16);
> > -        }
> > +        ff_hex_to_data(sess_config, config);
> >      }
> > 
> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Guo, Yejun April 29, 2021, 12:20 p.m. UTC | #3
> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> lance.lmwang@gmail.com
> Sent: 2021年4月28日 21:17
> To: ffmpeg-devel@ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> simplify the code with ff_hex_to_data
> 
> On Wed, Apr 28, 2021 at 12:26:54PM +0000, Guo, Yejun wrote:
> >
> >
> > > -----Original Message-----
> > > From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> > > lance.lmwang@gmail.com
> > > Sent: 2021年4月28日 18:47
> > > To: ffmpeg-devel@ffmpeg.org
> > > Cc: Limin Wang <lance.lmwang@gmail.com>
> > > Subject: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> > > simplify the code with ff_hex_to_data
> > >
> > > From: Limin Wang <lance.lmwang@gmail.com>
> > >
> > > please use tools/python/tf_sess_config.py to get the sess_config after
> that.
> > > note the byte order of session config is in normal order.
> > > bump the MICRO version for the config change.
> > >
> > > Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> > > ---
> > >  libavfilter/dnn/dnn_backend_tf.c | 42 +++++++------------------------------
> > >  libavfilter/version.h            |  2 +-
> > >  tools/python/tf_sess_config.py   | 45
> > > ++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 54 insertions(+), 35 deletions(-)
> > >  create mode 100644 tools/python/tf_sess_config.py
> > >
> > > diff --git a/libavfilter/dnn/dnn_backend_tf.c
> > > b/libavfilter/dnn/dnn_backend_tf.c
> > > index fb799d2..076dd3d 100644
> > > --- a/libavfilter/dnn/dnn_backend_tf.c
> > > +++ b/libavfilter/dnn/dnn_backend_tf.c
> > > @@ -28,6 +28,7 @@
> > >  #include "dnn_backend_native_layer_conv2d.h"
> > >  #include "dnn_backend_native_layer_depth2space.h"
> > >  #include "libavformat/avio.h"
> > > +#include "libavformat/internal.h"
> > >  #include "libavutil/avassert.h"
> > >  #include "../internal.h"
> > >  #include "dnn_backend_native_layer_pad.h"
> > > @@ -206,53 +207,26 @@ static DNNReturnType load_tf_model(TFModel
> > > *tf_model, const char *model_filename
> > >
> > >      // prepare the sess config data
> > >      if (tf_model->ctx.options.sess_config != NULL) {
> > > +        const char *config;
> > >          /*
> > >          tf_model->ctx.options.sess_config is hex to present the
> serialized
> > > proto
> > >          required by TF_SetConfig below, so we need to first generate
> the
> > > serialized
> > > -        proto in a python script, the following is a script example to
> > > generate
> > > -        serialized proto which specifies one GPU, we can change the
> script
> > > to add
> > > -        more options.
> > > -
> > > -        import tensorflow as tf
> > > -        gpu_options = tf.GPUOptions(visible_device_list='0')
> > > -        config = tf.ConfigProto(gpu_options=gpu_options)
> > > -        s = config.SerializeToString()
> > > -        b = ''.join("%02x" % int(ord(b)) for b in s[::-1])
> > > -        print('0x%s' % b)
> > > -
> > > -        the script output looks like: 0xab...cd, and then pass 0xab...cd to
> > > sess_config.
> > > +        proto in a python script, tools/python/tf_sess_config.py is a
> script
> > > example
> > > +        to generate the configs of sess_config.
> > >          */
> > > -        char tmp[3];
> > > -        tmp[2] = '\0';
> > > -
> > >          if (strncmp(tf_model->ctx.options.sess_config, "0x", 2) != 0) {
> > >              av_log(ctx, AV_LOG_ERROR, "sess_config should start with
> > > '0x'\n");
> > >              return DNN_ERROR;
> > >          }
> > > +        config = tf_model->ctx.options.sess_config + 2;
> > > +        sess_config_length = ff_hex_to_data(NULL, config);
> > >
> > > -        sess_config_length = strlen(tf_model->ctx.options.sess_config);
> > > -        if (sess_config_length % 2 != 0) {
> > > -            av_log(ctx, AV_LOG_ERROR, "the length of sess_config is
> not
> > > even (%s), "
> > > -                                      "please re-generate the
> > > config.\n",
> > > -
> > > tf_model->ctx.options.sess_config);
> > > -            return DNN_ERROR;
> > > -        }
> > > -
> > > -        sess_config_length -= 2; //ignore the first '0x'
> > > -        sess_config_length /= 2; //get the data length in byte
> > > -
> > > -        sess_config = av_malloc(sess_config_length);
> > > +        sess_config = av_mallocz(sess_config_length +
> > > AV_INPUT_BUFFER_PADDING_SIZE);
> >
> > just get a concern, why we need to add PADDING_SIZE here.
> > Will there be potential issue if not add?
> 
> I just want to make sure it's safe even if the sess_config_length is zero.
> 
ok, will push soon.
Limin Wang April 29, 2021, 1:06 p.m. UTC | #4
On Thu, Apr 29, 2021 at 12:20:17PM +0000, Guo, Yejun wrote:
> 
> 
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> > lance.lmwang@gmail.com
> > Sent: 2021年4月28日 21:17
> > To: ffmpeg-devel@ffmpeg.org
> > Subject: Re: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> > simplify the code with ff_hex_to_data
> > 
> > On Wed, Apr 28, 2021 at 12:26:54PM +0000, Guo, Yejun wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of
> > > > lance.lmwang@gmail.com
> > > > Sent: 2021年4月28日 18:47
> > > > To: ffmpeg-devel@ffmpeg.org
> > > > Cc: Limin Wang <lance.lmwang@gmail.com>
> > > > Subject: [FFmpeg-devel] [PATCH v3 1/2] avfilter/dnn/dnn_backend_tf:
> > > > simplify the code with ff_hex_to_data
> > > >
> > > > From: Limin Wang <lance.lmwang@gmail.com>
> > > >
> > > > please use tools/python/tf_sess_config.py to get the sess_config after
> > that.
> > > > note the byte order of session config is in normal order.
> > > > bump the MICRO version for the config change.
> > > >
> > > > Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> > > > ---
> > > >  libavfilter/dnn/dnn_backend_tf.c | 42 +++++++------------------------------
> > > >  libavfilter/version.h            |  2 +-
> > > >  tools/python/tf_sess_config.py   | 45
> > > > ++++++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 54 insertions(+), 35 deletions(-)
> > > >  create mode 100644 tools/python/tf_sess_config.py
> > > >
> > > > diff --git a/libavfilter/dnn/dnn_backend_tf.c
> > > > b/libavfilter/dnn/dnn_backend_tf.c
> > > > index fb799d2..076dd3d 100644
> > > > --- a/libavfilter/dnn/dnn_backend_tf.c
> > > > +++ b/libavfilter/dnn/dnn_backend_tf.c
> > > > @@ -28,6 +28,7 @@
> > > >  #include "dnn_backend_native_layer_conv2d.h"
> > > >  #include "dnn_backend_native_layer_depth2space.h"
> > > >  #include "libavformat/avio.h"
> > > > +#include "libavformat/internal.h"
> > > >  #include "libavutil/avassert.h"
> > > >  #include "../internal.h"
> > > >  #include "dnn_backend_native_layer_pad.h"
> > > > @@ -206,53 +207,26 @@ static DNNReturnType load_tf_model(TFModel
> > > > *tf_model, const char *model_filename
> > > >
> > > >      // prepare the sess config data
> > > >      if (tf_model->ctx.options.sess_config != NULL) {
> > > > +        const char *config;
> > > >          /*
> > > >          tf_model->ctx.options.sess_config is hex to present the
> > serialized
> > > > proto
> > > >          required by TF_SetConfig below, so we need to first generate
> > the
> > > > serialized
> > > > -        proto in a python script, the following is a script example to
> > > > generate
> > > > -        serialized proto which specifies one GPU, we can change the
> > script
> > > > to add
> > > > -        more options.
> > > > -
> > > > -        import tensorflow as tf
> > > > -        gpu_options = tf.GPUOptions(visible_device_list='0')
> > > > -        config = tf.ConfigProto(gpu_options=gpu_options)
> > > > -        s = config.SerializeToString()
> > > > -        b = ''.join("%02x" % int(ord(b)) for b in s[::-1])
> > > > -        print('0x%s' % b)
> > > > -
> > > > -        the script output looks like: 0xab...cd, and then pass 0xab...cd to
> > > > sess_config.
> > > > +        proto in a python script, tools/python/tf_sess_config.py is a
> > script
> > > > example
> > > > +        to generate the configs of sess_config.
> > > >          */
> > > > -        char tmp[3];
> > > > -        tmp[2] = '\0';
> > > > -
> > > >          if (strncmp(tf_model->ctx.options.sess_config, "0x", 2) != 0) {
> > > >              av_log(ctx, AV_LOG_ERROR, "sess_config should start with
> > > > '0x'\n");
> > > >              return DNN_ERROR;
> > > >          }
> > > > +        config = tf_model->ctx.options.sess_config + 2;
> > > > +        sess_config_length = ff_hex_to_data(NULL, config);
> > > >
> > > > -        sess_config_length = strlen(tf_model->ctx.options.sess_config);
> > > > -        if (sess_config_length % 2 != 0) {
> > > > -            av_log(ctx, AV_LOG_ERROR, "the length of sess_config is
> > not
> > > > even (%s), "
> > > > -                                      "please re-generate the
> > > > config.\n",
> > > > -
> > > > tf_model->ctx.options.sess_config);
> > > > -            return DNN_ERROR;
> > > > -        }
> > > > -
> > > > -        sess_config_length -= 2; //ignore the first '0x'
> > > > -        sess_config_length /= 2; //get the data length in byte
> > > > -
> > > > -        sess_config = av_malloc(sess_config_length);
> > > > +        sess_config = av_mallocz(sess_config_length +
> > > > AV_INPUT_BUFFER_PADDING_SIZE);
> > >
> > > just get a concern, why we need to add PADDING_SIZE here.
> > > Will there be potential issue if not add?
> > 
> > I just want to make sure it's safe even if the sess_config_length is zero.
> > 
> ok, will push soon.

I plan to submit a patch for ff_hex_to_data(), add one more parameter for data_size.

int ff_hex_to_data(uint8_t *data, const char *p);

to 

int ff_hex_to_data(uint8_t *data, int data_size, const char *p);

Or if the string size is large than alloc memory, it'll cause invalid memory access.

> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
diff mbox series

Patch

diff --git a/libavfilter/dnn/dnn_backend_tf.c b/libavfilter/dnn/dnn_backend_tf.c
index fb799d2..076dd3d 100644
--- a/libavfilter/dnn/dnn_backend_tf.c
+++ b/libavfilter/dnn/dnn_backend_tf.c
@@ -28,6 +28,7 @@ 
 #include "dnn_backend_native_layer_conv2d.h"
 #include "dnn_backend_native_layer_depth2space.h"
 #include "libavformat/avio.h"
+#include "libavformat/internal.h"
 #include "libavutil/avassert.h"
 #include "../internal.h"
 #include "dnn_backend_native_layer_pad.h"
@@ -206,53 +207,26 @@  static DNNReturnType load_tf_model(TFModel *tf_model, const char *model_filename
 
     // prepare the sess config data
     if (tf_model->ctx.options.sess_config != NULL) {
+        const char *config;
         /*
         tf_model->ctx.options.sess_config is hex to present the serialized proto
         required by TF_SetConfig below, so we need to first generate the serialized
-        proto in a python script, the following is a script example to generate
-        serialized proto which specifies one GPU, we can change the script to add
-        more options.
-
-        import tensorflow as tf
-        gpu_options = tf.GPUOptions(visible_device_list='0')
-        config = tf.ConfigProto(gpu_options=gpu_options)
-        s = config.SerializeToString()
-        b = ''.join("%02x" % int(ord(b)) for b in s[::-1])
-        print('0x%s' % b)
-
-        the script output looks like: 0xab...cd, and then pass 0xab...cd to sess_config.
+        proto in a python script, tools/python/tf_sess_config.py is a script example
+        to generate the configs of sess_config.
         */
-        char tmp[3];
-        tmp[2] = '\0';
-
         if (strncmp(tf_model->ctx.options.sess_config, "0x", 2) != 0) {
             av_log(ctx, AV_LOG_ERROR, "sess_config should start with '0x'\n");
             return DNN_ERROR;
         }
+        config = tf_model->ctx.options.sess_config + 2;
+        sess_config_length = ff_hex_to_data(NULL, config);
 
-        sess_config_length = strlen(tf_model->ctx.options.sess_config);
-        if (sess_config_length % 2 != 0) {
-            av_log(ctx, AV_LOG_ERROR, "the length of sess_config is not even (%s), "
-                                      "please re-generate the config.\n",
-                                      tf_model->ctx.options.sess_config);
-            return DNN_ERROR;
-        }
-
-        sess_config_length -= 2; //ignore the first '0x'
-        sess_config_length /= 2; //get the data length in byte
-
-        sess_config = av_malloc(sess_config_length);
+        sess_config = av_mallocz(sess_config_length + AV_INPUT_BUFFER_PADDING_SIZE);
         if (!sess_config) {
             av_log(ctx, AV_LOG_ERROR, "failed to allocate memory\n");
             return DNN_ERROR;
         }
-
-        for (int i = 0; i < sess_config_length; i++) {
-            int index = 2 + (sess_config_length - 1 - i) * 2;
-            tmp[0] = tf_model->ctx.options.sess_config[index];
-            tmp[1] = tf_model->ctx.options.sess_config[index + 1];
-            sess_config[i] = strtol(tmp, NULL, 16);
-        }
+        ff_hex_to_data(sess_config, config);
     }
 
     graph_def = read_graph(model_filename);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 4325551..f12bc87 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@ 
 
 #define LIBAVFILTER_VERSION_MAJOR   8
 #define LIBAVFILTER_VERSION_MINOR   0
-#define LIBAVFILTER_VERSION_MICRO 100
+#define LIBAVFILTER_VERSION_MICRO 101
 
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/tools/python/tf_sess_config.py b/tools/python/tf_sess_config.py
new file mode 100644
index 0000000..5705b1a
--- /dev/null
+++ b/tools/python/tf_sess_config.py
@@ -0,0 +1,45 @@ 
+# Copyright (c) 2021
+#
+# 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
+# ==============================================================================
+
+# verified with Python 3.6.8 on CentOS 7.2
+import tensorflow as tf
+
+visible_device_list = '0' # use , separator for more GPUs like '0, 1'
+per_process_gpu_memory_fraction = 0.9 # avoid out of memory
+intra_op_parallelism_threads = 2  # default in tensorflow
+inter_op_parallelism_threads = 5  # default in tensorflow
+
+gpu_options = tf.compat.v1.GPUOptions(
+              per_process_gpu_memory_fraction = per_process_gpu_memory_fraction,
+              visible_device_list = visible_device_list,
+              allow_growth = True)
+
+config = tf.compat.v1.ConfigProto(
+         allow_soft_placement = True,
+         log_device_placement = False,
+         intra_op_parallelism_threads = intra_op_parallelism_threads,
+         inter_op_parallelism_threads = inter_op_parallelism_threads,
+         gpu_options = gpu_options)
+
+s = config.SerializeToString()
+# print(list(map(hex, s)))  # print by json if need
+
+print('a serialized protobuf string for TF_SetConfig, note the byte order is in normal order.')
+b = ''.join(format(b,'02x') for b in s)
+print('0x%s' % b) # print by hex format