| Message ID | CAPYw7P7-mNMfw0tXBPPtH2CWZk0K4Vg1jcYUMTbG_=DjyYgk2A@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel] avcodec/yuv4enc: do not read past end of input in case of odd height | expand |
ons 2023-09-06 klockan 02:35 +0200 skrev Paul B Mahol: > + if (avctx->height & 1) { > + for (j = 0; j < avctx->width + 1 >> 1; j++) { Don't we usually wrap shifted expressions in parentheses? I know >> is lower presedence than + (a wtf in itself tbh) but I seem to recall parens being the norm in much of the codebase. /Tomas
Quoting Tomas Härdin (2023-09-06 08:16:12) > ons 2023-09-06 klockan 02:35 +0200 skrev Paul B Mahol: > > + if (avctx->height & 1) { > > + for (j = 0; j < avctx->width + 1 >> 1; j++) { > > Don't we usually wrap shifted expressions in parentheses? I know >> is > lower presedence than + (a wtf in itself tbh) but I seem to recall > parens being the norm in much of the codebase. Using ">> 1" to mean "/ 2" is a relic from the days of non-optimizing compilers anyway.
Anton Khirnov: > Quoting Tomas Härdin (2023-09-06 08:16:12) >> ons 2023-09-06 klockan 02:35 +0200 skrev Paul B Mahol: >>> + if (avctx->height & 1) { >>> + for (j = 0; j < avctx->width + 1 >> 1; j++) { >> >> Don't we usually wrap shifted expressions in parentheses? I know >> is >> lower presedence than + (a wtf in itself tbh) but I seem to recall >> parens being the norm in much of the codebase. > > Using ">> 1" to mean "/ 2" is a relic from the days of non-optimizing > compilers anyway. > Incorrect for signed expressions (right shift rounds to -inf, division to zero). - Andreas
From 8295be1415649255b26cfdb0308d7be208711b4d Mon Sep 17 00:00:00 2001 From: Paul B Mahol <onemda@gmail.com> Date: Wed, 6 Sep 2023 02:27:56 +0200 Subject: [PATCH] avcodec/yuv4enc: do not read past end of input in case of odd height Signed-off-by: Paul B Mahol <onemda@gmail.com> --- libavcodec/yuv4enc.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/libavcodec/yuv4enc.c b/libavcodec/yuv4enc.c index 8123260d5d..dd1874ff25 100644 --- a/libavcodec/yuv4enc.c +++ b/libavcodec/yuv4enc.c @@ -41,7 +41,7 @@ static int yuv4_encode_frame(AVCodecContext *avctx, AVPacket *pkt, u = pic->data[1]; v = pic->data[2]; - for (i = 0; i < avctx->height + 1 >> 1; i++) { + for (i = 0; i < avctx->height >> 1; i++) { for (j = 0; j < avctx->width + 1 >> 1; j++) { *dst++ = u[j] ^ 0x80; *dst++ = v[j] ^ 0x80; @@ -55,6 +55,17 @@ static int yuv4_encode_frame(AVCodecContext *avctx, AVPacket *pkt, v += pic->linesize[2]; } + if (avctx->height & 1) { + for (j = 0; j < avctx->width + 1 >> 1; j++) { + *dst++ = u[j] ^ 0x80; + *dst++ = v[j] ^ 0x80; + *dst++ = y[2 * j ]; + *dst++ = y[2 * j + 1]; + *dst++ = y[2 * j ]; + *dst++ = y[2 * j + 1]; + } + } + *got_packet = 1; return 0; } -- 2.39.1