Benjamin Larsson <[email protected]> writes:
> libavcodec/a64multienc.c: In function ‘a64multi_encode_frame’:
> libavcodec/a64multienc.c:342:17: warning: ‘buf’ may be used uninitialized in
> this function [-Wuninitialized]
>
> The compiler has trouble to figure out that the if block
> if (c->mc_frame_counter == c->mc_lifetime) {
> never should be entered with both values being 0. So add
> an explicit check on one of the parameters.
> ---
> libavcodec/a64multienc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/a64multienc.c b/libavcodec/a64multienc.c
> index c9d3b3c..9d3dca5 100644
> --- a/libavcodec/a64multienc.c
> +++ b/libavcodec/a64multienc.c
> @@ -304,7 +304,7 @@ static int a64multi_encode_frame(AVCodecContext *avctx,
> AVPacket *pkt,
> }
>
> /* lifetime reached so now convert X frames at once */
> - if (c->mc_frame_counter == c->mc_lifetime) {
> + if ((c->mc_frame_counter == c->mc_lifetime) && c->mc_lifetime) {
> req_size = 0;
> /* any frames to encode? */
> if (c->mc_lifetime) {
> --
If this is correct, simpler would be to remove the if (c->mc_lifetime)
condition on the last line above. However, I do not think this is the
case, at least it is not equivalent to the current code. If the !pict
condition is true, mc_lifetime and mc_frame_counter can both be set to
zero (in a rather convoluted way). This happens if encode() is called
twice with a null pict parameter, which is normal to flush the delayed
frames at the end of an encoding. On the second call with null input,
the encoder will return a zero-sized packet. On the third, it finally
reports end. This seems somewhat strange, so it may well be an error.
Assuming the final zero-length packet is incorrect, there is a simpler
solution to it all (untested):
diff --git a/libavcodec/a64multienc.c b/libavcodec/a64multienc.c
index c9d3b3c..9de5458 100644
--- a/libavcodec/a64multienc.c
+++ b/libavcodec/a64multienc.c
@@ -279,14 +279,10 @@ static int a64multi_encode_frame(AVCodecContext *avctx,
AVPacket *pkt,
/* no data, means end encoding asap */
if (!pict) {
+ /* limit lifetime to remaining frames */
+ c->mc_lifetime = c->mc_frame_counter;
/* all done, end encoding */
if (!c->mc_lifetime) return 0;
- /* no more frames in queue, prepare to flush remaining frames */
- if (!c->mc_frame_counter) {
- c->mc_lifetime = 0;
- }
- /* still frames in queue so limit lifetime to remaining frames */
- else c->mc_lifetime = c->mc_frame_counter;
/* still new data available */
} else {
/* fill up mc_meta_charset with data until lifetime exceeds */
@@ -306,8 +302,6 @@ static int a64multi_encode_frame(AVCodecContext *avctx,
AVPacket *pkt,
/* lifetime reached so now convert X frames at once */
if (c->mc_frame_counter == c->mc_lifetime) {
req_size = 0;
- /* any frames to encode? */
- if (c->mc_lifetime) {
req_size = charset_size + c->mc_lifetime*(screen_size +
colram_size);
if ((ret = ff_alloc_packet(pkt, req_size)) < 0) {
av_log(avctx, AV_LOG_ERROR, "Error getting output packet of
size %d.\n", req_size);
@@ -328,7 +322,6 @@ static int a64multi_encode_frame(AVCodecContext *avctx,
AVPacket *pkt,
/* advance pointers */
buf += charset_size;
charset += charset_size;
- }
/* write x frames to buf */
for (frame = 0; frame < c->mc_lifetime; frame++) {
--
Måns Rullgård
[email protected]
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