avformat/av1, avc, hevc: Remove av_freep()

ff_av1_filter_obus_buf() and ff_avc_parse_nal_units_buf() both have a
pointer-to-pointer parameter which they use to pass a newly allocated
buffer to the caller. And both functions freed what this pointer points to
before overwriting it. But no caller of these functions used this feature,
but some had to initialize the pointer just because of this. So remove
it and update the documentation of ff_av1_filter_obus_buf() wrt this fact.

ff_hevc_annexb2mp4_buf in contrast did not free the pointer. This has been
documented, too.

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

libavformat/av1.c

@@ -82,7 +82,6 @@ int ff_av1_filter_obus_buf(const uint8_t *in, uint8_t **out, int *size)
 
     memset(buf + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 
-    av_freep(out);
     *out  = buf;
     *size = len;
 

libavformat/av1.h

@@ -68,6 +68,7 @@ int ff_av1_filter_obus(AVIOContext *pb, const uint8_t *buf, int size);
  *
  * @return 0 in case of success, a negative AVERROR code in case of failure.
  *         On failure, out and size are unchanged
+ * @note *out will be treated as unintialized on input and will not be freed.
  */
 int ff_av1_filter_obus_buf(const uint8_t *in, uint8_t **out, int *size);
 

libavformat/avc.c

@@ -101,7 +101,6 @@ int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
 
     ff_avc_parse_nal_units(pb, buf_in, *size);
 
-    av_freep(buf);
     *size = avio_close_dyn_buf(pb, buf);
     return 0;
 }
@@ -109,7 +108,7 @@ int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
 int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
 {
     AVIOContext *sps_pb = NULL, *pps_pb = NULL, *sps_ext_pb = NULL;
-    uint8_t *buf = NULL, *end, *start = NULL;
+    uint8_t *buf, *end, *start;
     uint8_t *sps, *pps, *sps_ext;
     uint32_t sps_size = 0, pps_size = 0, sps_ext_size = 0;
     int ret, nb_sps = 0, nb_pps = 0, nb_sps_ext = 0;

libavformat/hevc.h

@@ -73,6 +73,7 @@ int ff_hevc_annexb2mp4(AVIOContext *pb, const uint8_t *buf_in,
  *        parameter set NAL units shall be written, may be NULL
  * @return 0 in case of success, a negative value corresponding to an AVERROR
  *         code in case of failure
+ * @note *buf_out will be treated as uninitialized on input and won't be freed.
  */
 int ff_hevc_annexb2mp4_buf(const uint8_t *buf_in, uint8_t **buf_out,
                            int *size, int filter_ps, int *ps_count);