daveidmx
11th January 2005, 02:23
@mediator:
I believe the spirit of your experiment may be similar to this test I ran earlier with The Two Towers SEE R1 D1.
Originally posted by daveidmx
To try to determine if this burpy video region was indeed the culprit, I did two short encodes of Two Towers. One containing only Chapter 2, the other containing Chapters 1-2. Tada! The one with only Chapter 2 is in sync, the one with Chapters 1-2 has skewed audio.
In that case, my solution was encode with a start time of about five seconds--similar to what your are requesting here. In that case, sync was restored. I suspect this was due to starting past the trouble spot in the video.
I performed your test as requested on The Sopranos Season 1 Episode 1 (R1). I performed four encodes with various start times. I end the encode at 2:08 as this is where dialogue begins and it is possible to check sync.
00:00:00:00-00:00:02:08 out of sync
00:00:01:00-00:00:02:08 out of sync
00:00:05:00-00:00:02:08 out of sync
00:00:13:03-00:00:02:08 out of sync
In this case, simply starting the encode at a later timecode is not a viable workaround. Here's why, I believe.
While it is true that the majority of NTSC "24p" DVD video follows a regular 3:2 pulldown cadence, it is not afaik a specification to do so. It appears that the encoder used for this title, among several others that I'm currently working with, alters the pulldown sequence occasionally throughout the encode. Each time through the course of the video there is a spurt of odd pulldown pattern, the audio sync is shifted. Since these "burps" are not confined to the start of the video, but instead sprinkled like pepper through the whole title, it is not possible to simply skip over them. Instead, it may be necessary to handle them.
For your consideration here is an exerpted bit of output from DGParse.exe on this title. I can provide the whole file if you'd like, but here I've included only the GOPs in the first 3000 (encoded) frames which bear unusual pattern breaks. I have been using this file to try to predect what the audio skew will be at any given time.
Now in a regular sequence, the video duration is the same when played back with our without 3:2.
normal sequence, 30 fps playback.
8 frames = 10/30 seconds = 333 ms
time 1/30s 1234567890
EVEN FIELD 0112345567
ODD FIELD 0123345677
normal sequence, 24 fps playback.
8 frames = 8/24 seconds = 333 ms
time 1/24s 12345678
EVEN FIELD 01234567
ODD FIELD 01234567
But now note particularily the sequences where there are many consecutive frames where RFF is set. (due to alternating TFF, this yields sequence 1-3-1-3 etc. instead of 0-1-2-3) If these sequence flags are not followed, but instead the video is assumed to be exactly 24p, the following occurs:
problem sequence, 30 fps playback.
8 frames = 12/30 seconds = 400 ms
time 1/30s 123456789012
EVEN FIELD 001223445667
ODD FIELD 011233455677
problem sequence, unguided 24 fps playback.
8 frames 8/24 seconds = 333 ms
time 1/24s 12345678
EVEN FIELD 01234567
ODD FILED 01234567
Here, when guidance flags are ignored the sequence plays back 67ms too fast. And of course the converse is true with sequences of 2-2-2-2. Do you think this could be the source of the problem?
Here is the excerpt from DGParse.exe.
Thanks! Let me know if you'd like me to run more tests.
David
DGParse 1.0.0 by Donald A. Graft
Encoded Frame: Display Frames -- Flags Byte
-------------------------------------------
[GOP START]
[CLIP IS TFF]
0: 0,0 -- 2 [vob/cell=1/1]
1: 1,1 -- 2 [vob/cell=1/1] [3:2 pattern break]
2: 2,2,3 -- 3 [vob/cell=1/1]
3: 3,4,4 -- 1 [vob/cell=1/1] [3:2 pattern break]
4: 5,5 -- 2 [vob/cell=1/1]
5: 6,6,7 -- 3 [vob/cell=1/1]
6: 7,8 -- 0 [vob/cell=1/1]
7: 8,9,9 -- 1 [vob/cell=1/1]
8: 10,10 -- 2 [vob/cell=1/1]
9: 11,11,12 -- 3 [vob/cell=1/1]
10: 12,13 -- 0 [vob/cell=1/1]
11: 13,14,14 -- 1 [vob/cell=1/1]
[GOP START]
120: 150,150,151 -- 3 [vob/cell=1/1] [3:2 pattern break]
121: 151,152,152 -- 1 [vob/cell=1/1] [3:2 pattern break]
122: 153,153,154 -- 3 [vob/cell=1/1] [3:2 pattern break]
123: 154,155,155 -- 1 [vob/cell=1/1] [3:2 pattern break]
124: 156,156,157 -- 3 [vob/cell=1/1] [3:2 pattern break]
125: 157,158 -- 0 [vob/cell=1/1]
126: 158,159,159 -- 1 [vob/cell=1/1]
127: 160,160 -- 2 [vob/cell=1/1]
128: 161,161,162 -- 3 [vob/cell=1/1]
129: 162,163 -- 0 [vob/cell=1/1]
130: 163,164,164 -- 1 [vob/cell=1/1]
131: 165,165 -- 2 [vob/cell=1/1]
[GOP START]
267: 335,335 -- 2 [vob/cell=1/1]
268: 336,336 -- 2 [vob/cell=1/1] [3:2 pattern break]
269: 337,337,338 -- 3 [vob/cell=1/1]
270: 338,339,339 -- 1 [vob/cell=1/1] [3:2 pattern break]
271: 340,340,341 -- 3 [vob/cell=1/1] [3:2 pattern break]
272: 341,342,342 -- 1 [vob/cell=1/1] [3:2 pattern break]
[GOP START]
273: 343,343,344 -- 3 [vob/cell=1/1] [3:2 pattern break]
274: 344,345,345 -- 1 [vob/cell=1/1] [3:2 pattern break]
275: 346,346,347 -- 3 [vob/cell=1/1] [3:2 pattern break]
276: 347,348 -- 0 [vob/cell=1/1]
277: 348,349,349 -- 1 [vob/cell=1/1]
278: 350,350 -- 2 [vob/cell=1/1]
279: 351,351,352 -- 3 [vob/cell=1/1]
280: 352,353 -- 0 [vob/cell=1/1]
281: 353,354,354 -- 1 [vob/cell=1/1]
282: 355,355 -- 2 [vob/cell=1/1]
283: 356,356,357 -- 3 [vob/cell=1/1]
284: 357,358 -- 0 [vob/cell=1/1]
[GOP START]
303: 381,381 -- 2 [vob/cell=1/1] [3:2 pattern break]
304: 382,382,383 -- 3 [vob/cell=1/1]
305: 383,384,384 -- 1 [vob/cell=1/1] [3:2 pattern break]
306: 385,385,386 -- 3 [vob/cell=1/1] [3:2 pattern break]
307: 386,387,387 -- 1 [vob/cell=1/1] [3:2 pattern break]
308: 388,388,389 -- 3 [vob/cell=1/1] [3:2 pattern break]
309: 389,390,390 -- 1 [vob/cell=1/1] [3:2 pattern break]
310: 391,391,392 -- 3 [vob/cell=1/1] [3:2 pattern break]
311: 392,393 -- 0 [vob/cell=1/1]
[GOP START]
2310: 2891,2891,2892 -- 3 [vob/cell=1/1]
2311: 2892,2893 -- 0 [vob/cell=1/1]
2312: 2893,2894,2894 -- 1 [vob/cell=1/1]
2313: 2895,2895 -- 2 [vob/cell=1/1]
2314: 2896,2896,2897 -- 3 [vob/cell=1/1]
2315: 2897,2898,2898 -- 1 [vob/cell=1/1] [3:2 pattern break]
2316: 2899,2899,2900 -- 3 [vob/cell=1/1] [3:2 pattern break]
2317: 2900,2901,2901 -- 1 [vob/cell=1/1] [3:2 pattern break]
2318: 2902,2902,2903 -- 3 [vob/cell=1/1] [3:2 pattern break]
2319: 2903,2904,2904 -- 1 [vob/cell=1/1] [3:2 pattern break]
2320: 2905,2905,2906 -- 3 [vob/cell=1/1] [3:2 pattern break]
2321: 2906,2907,2907 -- 1 [vob/cell=1/1] [3:2 pattern break]
[GOP START]
2322: 2908,2908,2909 -- 3 [vob/cell=1/1] [3:2 pattern break]
2323: 2909,2910,2910 -- 1 [vob/cell=1/1] [3:2 pattern break]
2324: 2911,2911 -- 2 [vob/cell=1/1]
2325: 2912,2912,2913 -- 3 [vob/cell=1/1]
2326: 2913,2914,2914 -- 1 [vob/cell=1/1] [3:2 pattern break]
2327: 2915,2915,2916 -- 3 [vob/cell=1/1] [3:2 pattern break]
2328: 2916,2917,2917 -- 1 [vob/cell=1/1] [3:2 pattern break]
2329: 2918,2918,2919 -- 3 [vob/cell=1/1] [3:2 pattern break]
2330: 2919,2920,2920 -- 1 [vob/cell=1/1] [3:2 pattern break]
2331: 2921,2921,2922 -- 3 [vob/cell=1/1] [3:2 pattern break]
2332: 2922,2923,2923 -- 1 [vob/cell=1/1] [3:2 pattern break]
2333: 2924,2924,2925 -- 3 [vob/cell=1/1] [3:2 pattern break]
[GOP START]
2334: 2925,2926,2926 -- 1 [vob/cell=1/1] [3:2 pattern break]
2335: 2927,2927,2928 -- 3 [vob/cell=1/1] [3:2 pattern break]
2336: 2928,2929,2929 -- 1 [vob/cell=1/1] [3:2 pattern break]
2337: 2930,2930,2931 -- 3 [vob/cell=1/1] [3:2 pattern break]
2338: 2931,2932,2932 -- 1 [vob/cell=1/1] [3:2 pattern break]
2339: 2933,2933,2934 -- 3 [vob/cell=1/1] [3:2 pattern break]
2340: 2934,2935,2935 -- 1 [vob/cell=1/1] [3:2 pattern break]
2341: 2936,2936,2937 -- 3 [vob/cell=1/1] [3:2 pattern break]
2342: 2937,2938,2938 -- 1 [vob/cell=1/1] [3:2 pattern break]
2343: 2939,2939,2940 -- 3 [vob/cell=1/1] [3:2 pattern break]
2344: 2940,2941,2941 -- 1 [vob/cell=1/1] [3:2 pattern break]
2345: 2942,2942,2943 -- 3 [vob/cell=1/1] [3:2 pattern break]
[GOP START]
2346: 2943,2944,2944 -- 1 [vob/cell=1/1] [3:2 pattern break]
2347: 2945,2945 -- 2 [vob/cell=1/1]
2348: 2946,2946 -- 2 [vob/cell=1/1] [3:2 pattern break]
[GOP START]
2349: 2947,2947 -- 2 [vob/cell=1/2] [3:2 pattern break]
2350: 2948,2948,2949 -- 3 [vob/cell=1/2]
2351: 2949,2950,2950 -- 1 [vob/cell=1/2] [3:2 pattern break]
2352: 2951,2951,2952 -- 3 [vob/cell=1/2] [3:2 pattern break]
2353: 2952,2953,2953 -- 1 [vob/cell=1/2] [3:2 pattern break]
2354: 2954,2954,2955 -- 3 [vob/cell=1/2] [3:2 pattern break]
2355: 2955,2956,2956 -- 1 [vob/cell=1/2] [3:2 pattern break]
2356: 2957,2957,2958 -- 3 [vob/cell=1/2] [3:2 pattern break]
2357: 2958,2959,2959 -- 1 [vob/cell=1/2] [3:2 pattern break]
2358: 2960,2960,2961 -- 3 [vob/cell=1/2] [3:2 pattern break]
2359: 2961,2962,2962 -- 1 [vob/cell=1/2] [3:2 pattern break]
2360: 2963,2963,2964 -- 3 [vob/cell=1/2] [3:2 pattern break]
[GOP START]
2361: 2964,2965,2965 -- 1 [vob/cell=1/2] [3:2 pattern break]
2362: 2966,2966,2967 -- 3 [vob/cell=1/2] [3:2 pattern break]
2363: 2967,2968,2968 -- 1 [vob/cell=1/2] [3:2 pattern break]
2364: 2969,2969,2970 -- 3 [vob/cell=1/2] [3:2 pattern break]
2365: 2970,2971,2971 -- 1 [vob/cell=1/2] [3:2 pattern break]
2366: 2972,2972,2973 -- 3 [vob/cell=1/2] [3:2 pattern break]
[GOP START]
2367: 2973,2974,2974 -- 1 [vob/cell=1/2] [3:2 pattern break]
2368: 2975,2975 -- 2 [vob/cell=1/2]
2369: 2976,2976,2977 -- 3 [vob/cell=1/2]
2370: 2977,2978 -- 0 [vob/cell=1/2]
2371: 2978,2979,2979 -- 1 [vob/cell=1/2]
2372: 2980,2980 -- 2 [vob/cell=1/2]
2373: 2981,2981,2982 -- 3 [vob/cell=1/2]
2374: 2982,2983 -- 0 [vob/cell=1/2]
2375: 2983,2984,2984 -- 1 [vob/cell=1/2]
2376: 2985,2985 -- 2 [vob/cell=1/2]
2377: 2986,2986,2987 -- 3 [vob/cell=1/2]
2378: 2987,2988 -- 0 [vob/cell=1/2]
[GOP START]
2511: 3153,3154,3154 -- 1 [vob/cell=1/2]
2512: 3155,3155 -- 2 [vob/cell=1/2]
2513: 3156,3156 -- 2 [vob/cell=1/2] [3:2 pattern break]
2514: 3157,3157 -- 2 [vob/cell=1/2] [3:2 pattern break]
2515: 3158,3158 -- 2 [vob/cell=1/2] [3:2 pattern break]
2516: 3159,3159 -- 2 [vob/cell=1/2] [3:2 pattern break]
2517: 3160,3160 -- 2 [vob/cell=1/2] [3:2 pattern break]
2518: 3161,3161 -- 2 [vob/cell=1/2] [3:2 pattern break]
2519: 3162,3162 -- 2 [vob/cell=1/2] [3:2 pattern break]
2520: 3163,3163 -- 2 [vob/cell=1/2] [3:2 pattern break]
2521: 3164,3164 -- 2 [vob/cell=1/2] [3:2 pattern break]
2522: 3165,3165 -- 2 [vob/cell=1/2] [3:2 pattern break]
[GOP START]
2523: 3166,3166 -- 2 [vob/cell=1/2] [3:2 pattern break]
2524: 3167,3167 -- 2 [vob/cell=1/2] [3:2 pattern break]
2525: 3168,3168 -- 2 [vob/cell=1/2] [3:2 pattern break]
2526: 3169,3169 -- 2 [vob/cell=1/2] [3:2 pattern break]
2527: 3170,3170 -- 2 [vob/cell=1/2] [3:2 pattern break]
2528: 3171,3171,3172 -- 3 [vob/cell=1/2]
2529: 3172,3173 -- 0 [vob/cell=1/2]
2530: 3173,3174,3174 -- 1 [vob/cell=1/2]
2531: 3175,3175 -- 2 [vob/cell=1/2]
2532: 3176,3176 -- 2 [vob/cell=1/2] [3:2 pattern break]
2533: 3177,3177 -- 2 [vob/cell=1/2] [3:2 pattern break]
2534: 3178,3178 -- 2 [vob/cell=1/2] [3:2 pattern break]
[GOP START]
2535: 3179,3179,3180 -- 3 [vob/cell=1/2]
2536: 3180,3181,3181 -- 1 [vob/cell=1/2] [3:2 pattern break]
2537: 3182,3182,3183 -- 3 [vob/cell=1/2] [3:2 pattern break]
2538: 3183,3184 -- 0 [vob/cell=1/2]
2539: 3184,3185,3185 -- 1 [vob/cell=1/2]
2540: 3186,3186 -- 2 [vob/cell=1/2]
2541: 3187,3187 -- 2 [vob/cell=1/2] [3:2 pattern break]
2542: 3188,3188,3189 -- 3 [vob/cell=1/2]
2543: 3189,3190,3190 -- 1 [vob/cell=1/2] [3:2 pattern break]
2544: 3191,3191 -- 2 [vob/cell=1/2]
2545: 3192,3192,3193 -- 3 [vob/cell=1/2]
2546: 3193,3194 -- 0 [vob/cell=1/2]
[GOP START]
2547: 3194,3195 -- 0 [vob/cell=1/2] [3:2 pattern break]
2548: 3195,3196,3196 -- 1 [vob/cell=1/2]
2549: 3197,3197 -- 2 [vob/cell=1/2]
2550: 3198,3198 -- 2 [vob/cell=1/2] [3:2 pattern break]
2551: 3199,3199 -- 2 [vob/cell=1/2] [3:2 pattern break]
2552: 3200,3200 -- 2 [vob/cell=1/2] [3:2 pattern break]
2553: 3201,3201,3202 -- 3 [vob/cell=1/2]
2554: 3202,3203 -- 0 [vob/cell=1/2]
2555: 3203,3204,3204 -- 1 [vob/cell=1/2]
2556: 3205,3205 -- 2 [vob/cell=1/2]
2557: 3206,3206,3207 -- 3 [vob/cell=1/2]
2558: 3207,3208 -- 0 [vob/cell=1/2]
[GOP START]
2661: 3336,3336,3337 -- 3 [vob/cell=1/2]
2662: 3337,3338 -- 0 [vob/cell=1/2]
2663: 3338,3339 -- 0 [vob/cell=1/2] [3:2 pattern break]
2664: 3339,3340,3340 -- 1 [vob/cell=1/2]
2665: 3341,3341,3342 -- 3 [vob/cell=1/2] [3:2 pattern break]
2666: 3342,3343 -- 0 [vob/cell=1/2]
2667: 3343,3344 -- 0 [vob/cell=1/2] [3:2 pattern break]
2668: 3344,3345,3345 -- 1 [vob/cell=1/2]
2669: 3346,3346,3347 -- 3 [vob/cell=1/2] [3:2 pattern break]
2670: 3347,3348 -- 0 [vob/cell=1/2]
2671: 3348,3349 -- 0 [vob/cell=1/2] [3:2 pattern break]
2672: 3349,3350,3350 -- 1 [vob/cell=1/2]
[GOP START]
2673: 3351,3351,3352 -- 3 [vob/cell=1/2] [3:2 pattern break]
2674: 3352,3353 -- 0 [vob/cell=1/2]
2675: 3353,3354 -- 0 [vob/cell=1/2] [3:2 pattern break]
2676: 3354,3355,3355 -- 1 [vob/cell=1/2]
2677: 3356,3356,3357 -- 3 [vob/cell=1/2] [3:2 pattern break]
2678: 3357,3358 -- 0 [vob/cell=1/2]
2679: 3358,3359 -- 0 [vob/cell=1/2] [3:2 pattern break]
2680: 3359,3360,3360 -- 1 [vob/cell=1/2]
2681: 3361,3361,3362 -- 3 [vob/cell=1/2] [3:2 pattern break]
2682: 3362,3363 -- 0 [vob/cell=1/2]
2683: 3363,3364 -- 0 [vob/cell=1/2] [3:2 pattern break]
2684: 3364,3365,3365 -- 1 [vob/cell=1/2]
[GOP START]
2685: 3366,3366,3367 -- 3 [vob/cell=1/2] [3:2 pattern break]
2686: 3367,3368 -- 0 [vob/cell=1/2]
2687: 3368,3369 -- 0 [vob/cell=1/2] [3:2 pattern break]
2688: 3369,3370,3370 -- 1 [vob/cell=1/2]
2689: 3371,3371,3372 -- 3 [vob/cell=1/2] [3:2 pattern break]
2690: 3372,3373 -- 0 [vob/cell=1/2]
2691: 3373,3374 -- 0 [vob/cell=1/2] [3:2 pattern break]
2692: 3374,3375,3375 -- 1 [vob/cell=1/2]
2693: 3376,3376,3377 -- 3 [vob/cell=1/2] [3:2 pattern break]
2694: 3377,3378 -- 0 [vob/cell=1/2]
2695: 3378,3379 -- 0 [vob/cell=1/2] [3:2 pattern break]
2696: 3379,3380,3380 -- 1 [vob/cell=1/2]
[GOP START]
2697: 3381,3381,3382 -- 3 [vob/cell=1/2] [3:2 pattern break]
2698: 3382,3383 -- 0 [vob/cell=1/2]
2699: 3383,3384 -- 0 [vob/cell=1/2] [3:2 pattern break]
2700: 3384,3385,3385 -- 1 [vob/cell=1/2]
2701: 3386,3386,3387 -- 3 [vob/cell=1/2] [3:2 pattern break]
2702: 3387,3388 -- 0 [vob/cell=1/2]
2703: 3388,3389 -- 0 [vob/cell=1/2] [3:2 pattern break]
2704: 3389,3390,3390 -- 1 [vob/cell=1/2]
2705: 3391,3391,3392 -- 3 [vob/cell=1/2] [3:2 pattern break]
2706: 3392,3393 -- 0 [vob/cell=1/2]
2707: 3393,3394 -- 0 [vob/cell=1/2] [3:2 pattern break]
2708: 3394,3395,3395 -- 1 [vob/cell=1/2]
[GOP START]
2709: 3396,3396,3397 -- 3 [vob/cell=1/2] [3:2 pattern break]
2710: 3397,3398 -- 0 [vob/cell=1/2]
2711: 3398,3399 -- 0 [vob/cell=1/2] [3:2 pattern break]
2712: 3399,3400,3400 -- 1 [vob/cell=1/2]
2713: 3401,3401,3402 -- 3 [vob/cell=1/2] [3:2 pattern break]
2714: 3402,3403 -- 0 [vob/cell=1/2]
2715: 3403,3404 -- 0 [vob/cell=1/2] [3:2 pattern break]
2716: 3404,3405,3405 -- 1 [vob/cell=1/2]
2717: 3406,3406,3407 -- 3 [vob/cell=1/2] [3:2 pattern break]
2718: 3407,3408 -- 0 [vob/cell=1/2]
2719: 3408,3409 -- 0 [vob/cell=1/2] [3:2 pattern break]
2720: 3409,3410,3410 -- 1 [vob/cell=1/2]
[GOP START]
2721: 3411,3411,3412 -- 3 [vob/cell=1/2] [3:2 pattern break]
2722: 3412,3413 -- 0 [vob/cell=1/2]
2723: 3413,3414 -- 0 [vob/cell=1/2] [3:2 pattern break]
[GOP START]
2724: 3414,3415,3415 -- 1 [vob/cell=1/2]
2725: 3416,3416,3417 -- 3 [vob/cell=1/2] [3:2 pattern break]
2726: 3417,3418 -- 0 [vob/cell=1/2]
2727: 3418,3419,3419 -- 1 [vob/cell=1/2]
2728: 3420,3420 -- 2 [vob/cell=1/2]
2729: 3421,3421,3422 -- 3 [vob/cell=1/2]
2730: 3422,3423 -- 0 [vob/cell=1/2]
2731: 3423,3424,3424 -- 1 [vob/cell=1/2]
2732: 3425,3425 -- 2 [vob/cell=1/2]
2733: 3426,3426,3427 -- 3 [vob/cell=1/2]
2734: 3427,3428 -- 0 [vob/cell=1/2]
2735: 3428,3429,3429 -- 1 [vob/cell=1/2]
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