I will attach a Flash sample that contains a h264 stream with a resolution change (320x256 -> 720x576). The sample is said to play with Flash, a similar mp4 sample decodes fine with ffmpeg.
For the attached sample, FFmpeg only shows artefacts from the moment of the resolution change on.
$ ffmpeg -i resolutionchange.flv -qscale 2 -an out.avi
ffmpeg version N-32788-g394781a, Copyright (c) 2000-2011 the FFmpeg developers
built on Sep 22 2011 14:49:18 with gcc 4.5.3
configuration: --cc=/usr/local/gcc-4.5.3/bin/gcc
libavutil 51. 17. 0 / 51. 17. 0
libavcodec 53. 16. 0 / 53. 16. 0
libavformat 53. 12. 0 / 53. 12. 0
libavdevice 53. 4. 0 / 53. 4. 0
libavfilter 2. 43. 2 / 2. 43. 2
libswscale 2. 1. 0 / 2. 1. 0
[flv @ 0x12b6780] Estimating duration from bitrate, this may be inaccurate
Seems stream 0 codec frame rate differs from container frame rate: 48.00 (48/1) -> 25.00 (25/1)
Input #0, flv, from 'resolutionchange.flv':
Duration: N/A, start: 0.002000, bitrate: N/A
Stream #0.0: Video: h264 (High), yuv420p, 320x256 [SAR 1024:1024 DAR 5:4], 25 tbr, 1k tbn, 48 tbc
Stream #0.1: Audio: aac, 44100 Hz, stereo, s16
[buffer @ 0x12be940] w:320 h:256 pixfmt:yuv420p tb:1/1000000 sar:1024/1024 sws_param:
[mpeg4 @ 0x12be120] Invalid pixel aspect ratio 1024/1024, limit is 255/255 reducing
Output #0, avi, to 'out.avi':
Metadata:
ISFT : Lavf53.12.0
Stream #0.0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 320x256 [SAR 1:1 DAR 5:4], q=2-31, 200 kb/s, 25 tbn, 25 tbc
Stream mapping:
Stream #0.0 -> #0.0 (h264 -> mpeg4)
Press [q] to stop, [?] for help
[h264 @ 0x12bcbc0] left block unavailable for requested intra4x4 mode -1 at 0 1
[h264 @ 0x12bcbc0] error while decoding MB 0 1, bytestream (48355)
[h264 @ 0x12bcbc0] concealing 320 DC, 320 AC, 320 MV errors
[h264 @ 0x12bcbc0] concealing 233 DC, 233 AC, 233 MV errors
[h264 @ 0x12bcbc0] concealing 293 DC, 293 AC, 293 MV errors
[h264 @ 0x12bcbc0] concealing 258 DC, 258 AC, 258 MV errors
[h264 @ 0x12bcbc0] Reference 2 >= 2
[h264 @ 0x12bcbc0] error while decoding MB 9 2, bytestream (3556)
[h264 @ 0x12bcbc0] concealing 320 DC, 320 AC, 320 MV errors
[h264 @ 0x12bcbc0] Reference 3 >= 3
[h264 @ 0x12bcbc0] error while decoding MB 11 1, bytestream (16377)
[h264 @ 0x12bcbc0] concealing 320 DC, 320 AC, 320 MV errors
[h264 @ 0x12bcbc0] concealing 192 DC, 192 AC, 192 MV errors
[h264 @ 0x12bcbc0] Reference 5 >= 5
...
[h264 @ 0x12bcbc0] error while decoding MB 14 2, bytestream (9337)
[h264 @ 0x12bcbc0] concealing 315 DC, 315 AC, 315 MV errors
[h264 @ 0x12bcbc0] concealing 215 DC, 215 AC, 215 MV errors
[h264 @ 0x12bcbc0] AVC: nal size 17728
[h264 @ 0x12bcbc0] no frame!
Error while decoding stream #0.0
frame= 285 fps= 0 q=2.0 Lsize= 2102kB time=00:00:11.92 bitrate=1444.5kbits/s
video:2089kB audio:0kB global headers:0kB muxing overhead 0.610160%
No useful warning is shown that the decoding will fail or has failed.
