[FFmpeg-devel] [PATCH] avformat/hlsenc: Check that data is set

Brendan McGrath redmcg at redmandi.dyndns.org
Sat Jan 20 02:59:30 EET 2018


If codecpar->extradata is not set (for example, when the stream goes
through the 'tee' muxer), then a segfault occurs.

This patch ensures the data variable is not null before attempting
to access it

Signed-off-by: Brendan McGrath <redmcg at redmandi.dyndns.org>
---
Before the var_stream_map option was available - I was using the tee
muxer to create each resolution as an individual stream.

When running this configuration after the most recent hlsenc change
I hit a segfault

The most simple command which recreates the segfault is:
ffmpeg -i in.ts -map 0:a -map 0:v -c:a aac -c:v h264 \
  -f tee [select=\'a,v\':f=hls]tv_hls_hd.m3u8

 libavformat/hlsenc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index 8ad906a..42e437f 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -308,7 +308,7 @@ static void write_codec_attr(AVStream *st, VariantStream *vs) {
 
     if (st->codecpar->codec_id == AV_CODEC_ID_H264) {
         uint8_t *data = st->codecpar->extradata;
-        if ((data[0] | data[1] | data[2]) == 0 && data[3] == 1 && (data[4] & 0x1F) == 7) {
+        if (data && (data[0] | data[1] | data[2]) == 0 && data[3] == 1 && (data[4] & 0x1F) == 7) {
             snprintf(attr, sizeof(attr),
                      "avc1.%02x%02x%02x", data[5], data[6], data[7]);
         } else {
-- 
2.7.4



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