avcodec/mpegvideo_enc: Don't segfault on unorthodox mpeg_quant
The (deprecated) field AVCodecContext.mpeg_quant has no range
restriction; MpegEncContext.mpeg_quant is restricted to 0..1.
If the former is set, the latter is overwritten with it without
checking the range. This can trigger an av_assert2() with the MPEG-4
encoder when writing said field.
Fix this by just setting MpegEncContext.mpeg_quant to 1 if
AVCodecContext.mpeg_quant is set.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
projects / ffmpeg / commit