On 2/5/22 01:10, Andreas Rheinhardt wrote:
1. This patch is absolutely unacceptable: It breaks ABI. 2. I am surprised that there is apparently only one user that actually wants this feature of state being an input parameter, namely (ff_)mpeg1_find_frame_end(). This means that this loop done before the new check should actually be made by this caller alone, obviating the need to change the signature. 3. Given that no user of this in libavformat wants this feature, changing it is IMO acceptable from an ABI-point of view.
I'll look into it.
4. There might be some slight changes introduced by this though: Consider 00 00 01 00 00 01 xy. If the initial state is -1, a call to avpriv_find_start_code() will treat the initial four bytes as start code and return a pointer to the byte preceding the second 0x01. If the user does not reset the start code between calls to avpriv_find_start_code(), the second call will combine the last zero byte of the start code with the rest to form another start code that partially overlaps with the earlier one. This is (probably) invalid data (definitely for H.262, H.264 and HEVC).
With input buffer 00 00 01 00 00 01 xy ... The code in master will (incorrectly) find a second start code at offset 7. It would need to check if (*start_code == 0x100) and invalidate it. -Scott _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
