[FFmpeg-cvslog] avcodec/dvenc: Avoid copying packet data, allow user-supplied buffers

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Sun Apr 25 01:43:26 2021 +0200| [835d8b7401466c2c22d4f439c3c331eb949d793e] | committer: Andreas Rheinhardt

avcodec/dvenc: Avoid copying packet data, allow user-supplied buffers

When the packet size is known in advance like here, one can avoid
an intermediate buffer for the packet data; this also makes it easy
to allow user-supplied buffers. Only one thing needed to be changed:
The earlier code relied on the buffer having been initially zeroed
by av_fast_padded_malloc(), so one now needs to zero the packet at
first.

Reviewed-by: James Almer <jamrial at gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=835d8b7401466c2c22d4f439c3c331eb949d793e
---

 libavcodec/dvenc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/dvenc.c b/libavcodec/dvenc.c
index 393c8b34e9..a464e3ed87 100644
--- a/libavcodec/dvenc.c
+++ b/libavcodec/dvenc.c
@@ -39,6 +39,7 @@
 #include "dv.h"
 #include "dv_profile_internal.h"
 #include "dv_tablegen.h"
+#include "encode.h"
 #include "fdctdsp.h"
 #include "internal.h"
 #include "mathops.h"
@@ -1170,8 +1171,10 @@ static int dvvideo_encode_frame(AVCodecContext *c, AVPacket *pkt,
     DVVideoContext *s = c->priv_data;
     int ret;
 
-    if ((ret = ff_alloc_packet2(c, pkt, s->sys->frame_size, 0)) < 0)
+    if ((ret = ff_get_encode_buffer(c, pkt, s->sys->frame_size, 0)) < 0)
         return ret;
+    /* Fixme: Only zero the part that is not overwritten later. */
+    memset(pkt->data, 0, pkt->size);
 
     c->pix_fmt                = s->sys->pix_fmt;
     s->frame                  = frame;
@@ -1209,10 +1212,11 @@ const AVCodec ff_dvvideo_encoder = {
     .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_DVVIDEO,
+    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
+                      AV_CODEC_CAP_SLICE_THREADS,
     .priv_data_size = sizeof(DVVideoContext),
     .init           = dvvideo_encode_init,
     .encode2        = dvvideo_encode_frame,
-    .capabilities   = AV_CODEC_CAP_SLICE_THREADS | AV_CODEC_CAP_FRAME_THREADS,
     .pix_fmts       = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE