[FFmpeg-devel] [PATCH 5/5] avformat/avc: support writting more than one sps/pps in ff_isom_write_avcc

[James Almer]

Addresses ticket #6864

Signed-off-by: James Almer <jamrial at gmail.com>
---
I don't have the h264 in isobmff spec at hand, so i just looked at what
the h264_mp4toannexb bsf does to handle more than one sps and pps and
worked with that.
If there's a pps limit it's not currently enforced, but adding it is
trivial. The sps limit i added is arbitrarily 2^5-1, as that's the
amount of bits available for it.

 libavformat/avc.c | 50 +++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/libavformat/avc.c b/libavformat/avc.c
index 6ef6e08778..634324aee5 100644
--- a/libavformat/avc.c
+++ b/libavformat/avc.c
@@ -105,10 +105,11 @@ 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;
     uint8_t *buf = NULL, *end, *start;
     uint8_t *sps = NULL, *pps = NULL;
     uint32_t sps_size = 0, pps_size = 0;
-    int ret;
+    int ret, nb_sps = 0, nb_pps = 0;
 
     if (len < 6)
         return AVERROR_INVALIDDATA;
@@ -126,6 +127,13 @@ int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
     start = buf;
     end = buf + len;
 
+    ret = avio_open_dyn_buf(&sps_pb);
+    if (ret < 0)
+        goto fail;
+    ret = avio_open_dyn_buf(&pps_pb);
+    if (ret < 0)
+        goto fail;
+
     /* look for sps and pps */
     while (end - buf > 4) {
         uint32_t size;
@@ -135,35 +143,51 @@ int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
         nal_type = buf[0] & 0x1f;
 
         if (nal_type == 7) { /* SPS */
-            sps = buf;
-            sps_size = size;
+            if (size > UINT16_MAX) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            avio_wb16(sps_pb, size);
+            avio_write(sps_pb, buf, size);
+            nb_sps++;
         } else if (nal_type == 8) { /* PPS */
-            pps = buf;
-            pps_size = size;
+            if (size > UINT16_MAX) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            avio_wb16(pps_pb, size);
+            avio_write(pps_pb, buf, size);
+            nb_pps++;
         }
 
         buf += size;
     }
+    sps_size = avio_close_dyn_buf(sps_pb, &sps);
+    pps_size = avio_close_dyn_buf(pps_pb, &pps);
 
-    if (!sps || !pps || sps_size < 4 || sps_size > UINT16_MAX || pps_size > UINT16_MAX) {
+    if (nb_sps > 31 || sps_size < 6 || !pps_size) {
         ret = AVERROR_INVALIDDATA;
         goto fail;
     }
 
     avio_w8(pb, 1); /* version */
-    avio_w8(pb, sps[1]); /* profile */
-    avio_w8(pb, sps[2]); /* profile compat */
-    avio_w8(pb, sps[3]); /* level */
+    avio_w8(pb, sps[3]); /* profile */
+    avio_w8(pb, sps[4]); /* profile compat */
+    avio_w8(pb, sps[5]); /* level */
     avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
-    avio_w8(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
+    avio_w8(pb, 0xe0 | nb_sps); /* 3 bits reserved (111) + 5 bits number of sps */
 
-    avio_wb16(pb, sps_size);
     avio_write(pb, sps, sps_size);
-    avio_w8(pb, 1); /* number of pps */
-    avio_wb16(pb, pps_size);
+    avio_w8(pb, nb_pps); /* number of pps */
     avio_write(pb, pps, pps_size);
 
 fail:
+    if (!sps)
+        avio_close_dyn_buf(sps_pb, &sps);
+    if (!pps)
+        avio_close_dyn_buf(pps_pb, &pps);
+    av_free(sps);
+    av_free(pps);
     av_free(start);
 
     return ret;
-- 
2.15.0