[FFmpeg-devel] [PATCH] lavf: split packets before muxing.

Michael Niedermayer michaelni at gmx.at
Sat Dec 8 19:42:11 CET 2012


On Fri, Dec 07, 2012 at 03:21:02AM +0100, Clément Bœsch wrote:
> On Thu, Dec 06, 2012 at 01:51:36PM +0100, Nicolas George wrote:
> > Le sextidi 16 frimaire, an CCXXI, Clément Bœsch a écrit :
> > > New version merging the side data back after muxing.
> > 
> > Sorry to take the train already rolling (av_packet_*_side_data() are
> > undocumented): would it not be simpler to copy the packet structure and
> > adjust the size / split the side data in the copy?
> > 
> > I find that schemes like "do X; something; undo X" are usually a bad idea.
> > 
> 
> So something like attached instead?
> 
> [...]
> 
> -- 
> Clément B.

>  mux.c |   20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> d7b715e6b1ee3bc9b350902795c63b4886a6e871  0001-lavf-split-packets-before-muxing.patch
> From 8de676cadfdd2cf186d02f83b4decddbec021d8f Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <ubitux at gmail.com>
> Date: Mon, 3 Dec 2012 23:13:53 +0100
> Subject: [PATCH] lavf: split packets before muxing.
> 
> After demuxing, data and side are merged. Before decoding, they are
> split. Encoder will perform with data and side split. This means that a
> muxer can receive split data (after encoding) but also merged data (if
> called directly after demuxing). This commit makes sure data and side
> are split for the muxer.
> ---
>  libavformat/mux.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/mux.c b/libavformat/mux.c
> index 9bcee99..f7bb3ad 100644
> --- a/libavformat/mux.c
> +++ b/libavformat/mux.c
> @@ -484,13 +484,25 @@ static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
>      return 0;
>  }
>  
> +static inline int split_write_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    int ret;
> +    AVPacket spkt = *pkt;
> +
> +    av_packet_split_side_data(&spkt);
> +    ret = s->oformat->write_packet(s, &spkt);
> +    spkt.data = NULL;
> +    av_destruct_packet(&spkt);

doesnt this leak and crash the next muxer if 2 are called on the
same packet ?

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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