James Almer: > On 3/29/2021 2:20 PM, Andreas Rheinhardt wrote: >> James Almer: >>> On 3/29/2021 2:12 PM, Andreas Rheinhardt wrote: >>>> AC-3 and EAC-3 are codecs whose packet sizes are known in advance, >>>> so one can use the min_size parameter of ff_alloc_packet2() to >>>> allocate exactly this amount. This avoids a memcpy later in >>>> av_packet_make_refcounted() in encode_simple_internal(). >>>> >>>> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> >>>> --- >>>> Is there actually a reason not to use av_new_packet() (or >>>> ff_get_encode_buffer()) directly? >>> >>> I'm waiting for the bump when avcodec_encode_*() are removed before >>> making most encoders DR1, and thus use ff_get_encode_buffer(). And that >>> includes this one. >>> >>> This patch LGTM, but it may not be worth applying if it's going to be >>> changed again very soon. >>> >> >> What are your plans for encoders that don't know the final size in >> advance and overallocate? > > Keep using av_packet_shrink() like now. >
But only a few encoders only use av_shrink_packet(); most just use ff_alloc_packet2() with min_size == 0 (in which case the returned packet isn't refcounted) and just set the packet's size. The av_packet_make_refcounted() in encode_simple_internal() then allocates the final buffer (and zeroes the padding). So do you intend to return these oversized buffers to the user or do you intend to use ff_get_encode_buffer() for allocating the packet's buffer when it isn't refcounted? >> >>>> >>>> libavcodec/ac3enc.c | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c >>>> index 4cfd0afe12..fc4d45651d 100644 >>>> --- a/libavcodec/ac3enc.c >>>> +++ b/libavcodec/ac3enc.c >>>> @@ -1759,7 +1759,8 @@ int >>>> ff_ac3_encode_frame_common_end(AVCodecContext *avctx, AVPacket *avpkt, >>>> ac3_quantize_mantissas(s); >>>> - if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size, 0)) >>>> < 0) >>>> + ret = ff_alloc_packet2(avctx, avpkt, s->frame_size, >>>> s->frame_size); >>>> + if (ret < 0) >>>> return ret; >>>> ac3_output_frame(s, avpkt->data); >>>> >>> >>> _______________________________________________ >>> ffmpeg-devel mailing list >>> ffmpeg-devel@ffmpeg.org >>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel >>> >>> To unsubscribe, visit link above, or email >>> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> To unsubscribe, visit link above, or email >> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". >> > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
