On Sat, May 17, 2014 at 05:35:14PM +0200, Anton Khirnov wrote: > > On Wed, 14 May 2014 15:56:17 +0200, Alessandro Ghedini > <[email protected]> wrote: > > On lun, mag 12, 2014 at 07:31:13 +0200, Anton Khirnov wrote: > > > > > > On Wed, 7 May 2014 00:37:41 +0200, Alessandro Ghedini > > > <[email protected]> wrote: > > > > Hi, > > > > > > > > I've been working on merging the GIF encoder from ffmpeg, since libav's > > > > doesn't > > > > seem to work very well (in my tests anyway), and my initial approach > > > > has been to > > > > simply copy/paste lavc/gif.{c,h} and lavf/gif.c, make them compile and > > > > see how > > > > it goes (I'm using libav.git). > > > > > > > > While I've been able to compile the whole thing (with a little bit of > > > > work, due > > > > to missing av_copy_packet() and ff_alloc_packet2()), I'm still having > > > > problems > > > > apparently related to pixel formats. > > > > > > > > Basically, when I'm using ffmpeg (ffmpeg -i test.mkv test.ffmpeg.gif) > > > > it selects > > > > "bgr8" and everything goes fine. > > > > > > > > > > I think using av_packet_ref() really should work, there seems to be no > > > reason to > > > copy it. Can you post the code that fails somewhere? > > > > So, av_copy_packet() looks like this: > > > > *dst = *src; > > return copy_packet_data(dst, src, 0); > > > > where copy_data_packet() does the av_buffer_ref() thing, and copies the side > > data. So I simply replaced copy_packet_data() with av_packet_ref() and then > > used > > av_packet_unref() instead of av_free_packet()/av_freep(), like this: > > > > diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c > > index c3787e1..c4a0d32 100644 > > --- a/libavcodec/avpacket.c > > +++ b/libavcodec/avpacket.c > > @@ -262,7 +262,7 @@ FF_ENABLE_DEPRECATION_WARNINGS > > int av_copy_packet(AVPacket *dst, const AVPacket *src) > > { > > *dst = *src; > > - return copy_packet_data(dst, src, 0); > > + return av_packet_ref(dst, src); > > } > > > > void av_packet_free_side_data(AVPacket *pkt) > > diff --git a/libavformat/gif.c b/libavformat/gif.c > > index e817121..4230756 100644 > > --- a/libavformat/gif.c > > +++ b/libavformat/gif.c > > @@ -165,7 +165,7 @@ static int flush_packet(AVFormatContext *s, AVPacket > > *new) > > > > avio_write(pb, pkt->data, pkt->size); > > > > - av_free_packet(gif->prev_pkt); > > + av_packet_unref(gif->prev_pkt); > > if (new) > > av_copy_packet(gif->prev_pkt, new); > > > > @@ -191,7 +191,7 @@ static int gif_write_trailer(AVFormatContext *s) > > AVIOContext *pb = s->pb; > > > > flush_packet(s, NULL); > > - av_freep(&gif->prev_pkt); > > + av_packet_unref(gif->prev_pkt); > > avio_w8(pb, 0x3b); > > > > return 0; > > > > But it spits out a whole binch of: > > > > *** Error in `devel/libav/avconv': free(): invalid pointer: > > 0x000000000a279bd0 *** > > *** Error in `devel/libav/avconv': corrupted double-linked list: > > 0x0000000009c715c0 *** > > > > and then it segfaults. The only difference I can see between > > copy_packet_data() > > and av_packet_ref() is the way side data is copied: the former uses ffmpeg's > > av_copy_packet_side_data() while the latter uses av_packet_copy_props(). So > > I > > replaced the av_packet_copy_props() call with the ffmpeg thing like this: > > > > Aren't you confusing the AVPacket itself (which is a container for data) with > the data it contains?
Possibly.
> The two must be allocated and freed separately, and av_packet_ref/unref only
> handles the data.
Aren't they already? The prev_pkt is allocated with av_malloc() (though I guess
I shouldn't have removed the av_freep()).
> Check out the attached patch, it seems to work for me.
Well, now it doesn't segfault or spit free() errors, but it still fails with:
[gif @ 0x31b3820] Invalid palette extradata
av_interleaved_write_frame(): Invalid data found when processing input
so it looks like the side data is still not copied properly. What fixes it is
the following:
diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index c0a0f8c..f3edd37 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -327,20 +327,25 @@ int av_packet_copy_props(AVPacket *dst, const AVPacket
*src)
dst->stream_index = src->stream_index;
dst->side_data_elems = src->side_data_elems;
- for (i = 0; i < src->side_data_elems; i++) {
- enum AVPacketSideDataType type = src->side_data[i].type;
- int size = src->side_data[i].size;
- uint8_t *src_data = src->side_data[i].data;
- uint8_t *dst_data = av_packet_new_side_data(dst, type, size);
-
- if (!dst_data) {
- av_packet_free_side_data(dst);
- return AVERROR(ENOMEM);
+ if (src->side_data_elems) {
+ DUP_DATA(dst->side_data, src->side_data,
+ src->side_data_elems * sizeof(*src->side_data), 0,
ALLOC_MALLOC);
+ if (src != dst) {
+ memset(dst->side_data, 0,
+ src->side_data_elems * sizeof(*src->side_data));
+ }
+ for (i = 0; i < src->side_data_elems; i++) {
+ DUP_DATA(dst->side_data[i].data, src->side_data[i].data,
+ src->side_data[i].size, 1, ALLOC_MALLOC);
+ dst->side_data[i].size = src->side_data[i].size;
+ dst->side_data[i].type = src->side_data[i].type;
}
- memcpy(dst_data, src_data, size);
}
-
+ dst->side_data_elems = src->side_data_elems;
return 0;
+
+failed_alloc:
+ return AVERROR(ENOMEM);
}
i.e. doing what ffmpeg's av_copy_packet_side_data() does, but in
av_packet_copy_props(). Not sure if it's correct.
Your static prev_pkt approach looks better than the original av_malloc() one so
I kept it and pushed to my fork along with the side data copying above.
The wonky colors problem persists though.
Cheers
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