[FFmpeg-devel] [PATCH 4/7] lavc: move decoder bsf init into decoder-specific code

[Andreas Rheinhardt]

James Almer:
> On 3/10/2021 9:03 AM, Anton Khirnov wrote:
>> ---
>>   libavcodec/decode.c | 8 +++++++-
>>   libavcodec/decode.h | 6 ------
>>   libavcodec/utils.c  | 6 ------
>>   3 files changed, 7 insertions(+), 13 deletions(-)
>>
>> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
>> index e5a301ec58..d25b15e95a 100644
>> --- a/libavcodec/decode.c
>> +++ b/libavcodec/decode.c
>> @@ -184,7 +184,7 @@ static int extract_packet_props(AVCodecInternal
>> *avci, const AVPacket *pkt)
>>       return 0;
>>   }
>>   -int ff_decode_bsfs_init(AVCodecContext *avctx)
>> +static int decode_bsfs_init(AVCodecContext *avctx)
>>   {
>>       AVCodecInternal *avci = avctx->internal;
>>       int ret;
>> @@ -2010,6 +2010,8 @@ int ff_reget_buffer(AVCodecContext *avctx,
>> AVFrame *frame, int flags)
>>     int ff_decode_preinit(AVCodecContext *avctx)
>>   {
>> +    int ret = 0;
>> +
>>       /* if the decoder init function was already called previously,
>>        * free the already allocated subtitle_header before overwriting
>> it */
>>       av_freep(&avctx->subtitle_header);
>> @@ -2046,5 +2048,9 @@ FF_ENABLE_DEPRECATION_WARNINGS
>>           avctx->export_side_data |= AV_CODEC_EXPORT_DATA_MVS;
>>       }
>>   +    ret = decode_bsfs_init(avctx);
> 
> Did you try to run fate with THREADS set to something other than 1? This
> moves the bsfs initialization after ff_thread_init(), so all the copies
> of avctx in frame threading scenarios will be missing the bsfs requested
> by the decoder.
> 

For frame threaded decoders the codec's decode function is directly run
with the child AVCodecContext; they don't need the bsfs: The parent's
bsf has already been run on the packets before the frame threaded code
is reached.

> fate-vp9 should be enough to confirm this, since afaik it's the only
> frame threaded decoder that uses a bsf.
> 
>> +    if (ret < 0)
>> +        return ret;
>> +
>>       return 0;
>>   }
>> diff --git a/libavcodec/decode.h b/libavcodec/decode.h
>> index a865fe954f..1467b1eb33 100644
>> --- a/libavcodec/decode.h
>> +++ b/libavcodec/decode.h
>> @@ -69,12 +69,6 @@ int ff_decode_get_packet(AVCodecContext *avctx,
>> AVPacket *pkt);
>>    */
>>   int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame);
>>   -/**
>> - * Called during avcodec_open2() to initialize avctx->internal->bsf.
>> - * The bsf should be freed with av_bsf_free().
>> - */
>> -int ff_decode_bsfs_init(AVCodecContext *avctx);
>> -
>>   /**
>>    * Make sure avctx.hw_frames_ctx is set. If it's not set, the
>> function will
>>    * try to allocate it from hw_device_ctx. If that is not possible,
>> an error
>> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
>> index 6d5aeb4eaf..918cb1b4d1 100644
>> --- a/libavcodec/utils.c
>> +++ b/libavcodec/utils.c
>> @@ -730,12 +730,6 @@ int attribute_align_arg
>> avcodec_open2(AVCodecContext *avctx, const AVCodec *code
>>               goto free_and_end;
>>       }
>>   -    if (av_codec_is_decoder(avctx->codec)) {
>> -        ret = ff_decode_bsfs_init(avctx);
>> -        if (ret < 0)
>> -            goto free_and_end;
>> -    }
>> -
>>       if (HAVE_THREADS
>>           && !(avci->frame_thread_encoder &&
>> (avctx->active_thread_type&FF_THREAD_FRAME))) {
>>           ret = ff_thread_init(avctx);
>>
> 
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