[FFmpeg-devel] [PATCH] avcodec/libx264: remove FF_CODEC_CAP_INIT_THREADSAFE flag

[Marton Balint]

On Sat, 20 Oct 2018, Hendrik Leppkes wrote:

> On Sat, Oct 20, 2018 at 12:35 PM Marton Balint <cus at passwd.hu> wrote:
>>
>> Libx264 uses strtok which is not thread safe. Strtok is used in
>> x264_param_default_preset in param_apply_tune in x264/common/base.c.
>> Therefore the flag must be removed.
>>
>> Fixes ticket #7446.
>>
>> Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>  libavcodec/libx264.c | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
>> index 54e6703d73..d6367bf557 100644
>> --- a/libavcodec/libx264.c
>> +++ b/libavcodec/libx264.c
>> @@ -1063,8 +1063,7 @@ AVCodec ff_libx264_encoder = {
>>      .priv_class       = &x264_class,
>>      .defaults         = x264_defaults,
>>      .init_static_data = X264_init_static,
>> -    .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
>> -                        FF_CODEC_CAP_INIT_CLEANUP,
>> +    .caps_internal    = FF_CODEC_CAP_INIT_CLEANUP,
>>      .wrapper_name     = "libx264",
>>  };
>>  #endif
>> @@ -1115,8 +1114,7 @@ AVCodec ff_libx262_encoder = {
>>      .priv_class       = &X262_class,
>>      .defaults         = x264_defaults,
>>      .pix_fmts         = pix_fmts_8bit,
>> -    .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
>> -                        FF_CODEC_CAP_INIT_CLEANUP,
>> +    .caps_internal    = FF_CODEC_CAP_INIT_CLEANUP,
>>      .wrapper_name     = "libx264",
>>  };
>>  #endif
>> --
>> 2.16.4
>>
>
> Was this ever reported to x264?

Not by me.

> Theoretically some other library or another part of a calling 
> application could still use strtok and break it.

I agree, this should be fixed in x264 as well, but until then it 
seems harmless to remove the flag.

Regards,
Marton