[FFmpeg-devel] [PATCH 01/13] avformat/mux: Move packet references

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Wed Sep 25 13:57:00 EEST 2019


Andreas Rheinhardt:
> Andreas Rheinhardt:
>> In the common case that the input packet was already refcounted,
>> ff_interleave_add_packet would allocate a new AVPacketList, use
>> av_packet_ref to create a new reference to the buffer for the
>> AVPacketList's packet, interleave the packet and finally unreference
>> the original input packet.
>> This commit changes this: It uses av_packet_move_ref to transfer
>> the packet to its destination. In case the input packet is refcounted,
>> this saves an allocation and a free (of an AVBufferRef); if not, the
>> packet is made refcounted before moving it. When the input packet has
>> side data, one saves even more than one allocation+free.
>>
>> Furthermore, when the packet is in reality an uncoded frame, a hacky
>> ad-hoc variant of av_packet_move_ref has been employed. Not any more.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>> ---
>>  libavformat/mux.c | 11 ++++-------
>>  1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/libavformat/mux.c b/libavformat/mux.c
>> index 8ab5ea8c2b..ac370fb24d 100644
>> --- a/libavformat/mux.c
>> +++ b/libavformat/mux.c
>> @@ -930,17 +930,16 @@ int ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
>>      if ((pkt->flags & AV_PKT_FLAG_UNCODED_FRAME)) {
>>          av_assert0(pkt->size == UNCODED_FRAME_PACKET_SIZE);
>>          av_assert0(((AVFrame *)pkt->data)->buf);
>> -        this_pktl->pkt = *pkt;
>> -        pkt->buf = NULL;
>> -        pkt->side_data = NULL;
>> -        pkt->side_data_elems = 0;
>>      } else {
>> -        if ((ret = av_packet_ref(&this_pktl->pkt, pkt)) < 0) {
>> +        if ((ret = av_packet_make_refcounted(pkt)) < 0) {
>>              av_free(this_pktl);
>>              return ret;
>>          }
>>      }
>>  
>> +    av_packet_move_ref(&this_pktl->pkt, pkt);
>> +    pkt = &this_pktl->pkt;
>> +
>>      if (s->streams[pkt->stream_index]->last_in_packet_buffer) {
>>          next_point = &(st->last_in_packet_buffer->next);
>>      } else {
>> @@ -989,8 +988,6 @@ next_non_null:
>>      s->streams[pkt->stream_index]->last_in_packet_buffer =
>>          *next_point                                      = this_pktl;
>>  
>> -    av_packet_unref(pkt);
>> -
>>      return 0;
>>  }
>>  
>>
> Ping for this patch and the remaining unmerged patches in this
> patchset (patches 1, 2, 4, 5, 7-13).
> 
> - Andreas
> 
Another ping.

- Andreas


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