avcenc: Only do startcode escaping if the next byte requires it
Section 7.4.1 in the H.264 standard says that the only valid bytes
to follow a sequence that starts with 0x000003 are 0x00, 0x01,
0x02 or 0x03.
This makes EncodeDecodeTest pass properly when decoding using
OMX.google.h264.decoder, which is strict about the forbidden
escape sequences.
Change-Id: Ice113d9b934015003ea9cb10d0b21cee4d18d774
diff --git a/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp b/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp
index 0e3037f..d71c327 100644
--- a/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp
+++ b/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp
@@ -103,6 +103,15 @@
{
num_bits -= 8;
byte = (current_word >> num_bits) & 0xFF;
+ if (stream->count_zeros == 2)
+ { /* for num_bits = 32, this can add 2 more bytes extra for EPBS */
+ if (byte <= 3)
+ {
+ *write_pnt++ = 0x3;
+ stream->write_pos++;
+ stream->count_zeros = 0;
+ }
+ }
if (byte != 0)
{
*write_pnt++ = byte;
@@ -114,12 +123,6 @@
stream->count_zeros++;
*write_pnt++ = byte;
stream->write_pos++;
- if (stream->count_zeros == 2)
- { /* for num_bits = 32, this can add 2 more bytes extra for EPBS */
- *write_pnt++ = 0x3;
- stream->write_pos++;
- stream->count_zeros = 0;
- }
}
}