[Libav-user] decoding to external buffers, AV_CODEC_CAP_DR1

KNU knu at free.fr
Thu Nov 4 12:59:40 EET 2021

Hi all,

I'm working on a decoder specifically geared towards QTRLE and PCM (in 
MOV container).

In order to avoid time consumming copies, I'd like to provide my own 
output buffers to the codecs.

I can see in the sources that both codecs support external buffers :

FFmpeg/libavcodec/qtrle.c > line 594 > ".capabilities=AV_CODEC_CAP_DR1"
FFmpeg/libavcodec/pcm.c > line 559 > ".capabilities=AV_CODEC_CAP_DR1"

Unfortunately, the "flags" parameter of my get_buffer2 callback do not 
have the AV_CODEC_CAP_DR1 flag set.

So, according to
"If AV_CODEC_CAP_DR1 is not set then get_buffer2() must call 
avcodec_default_get_buffer2() instead of providing buffers allocated by 
some other means." ;-(

I tried to set the "flags" property of my AVCodecContexts to 
AV_CODEC_CAP_DR1 (codec_ctx->flags = AV_CODEC_CAP_DR1) but it does not help.

What am I doing wrong ? Is there something that I don't understand ?

Thanks for your help !


More information about the Libav-user mailing list