[MPlayer-dev-eng] [PATCH] automatic fps for mpeg4 raw/in TS
Nico Sabbi
nsabbi at tiscali.it
Tue Jan 11 21:27:20 CET 2005
Nico Sabbi wrote:
> Nico Sabbi wrote:
>
>> Nico Sabbi wrote:
>>
>>> Michael Niedermayer wrote:
>>>
>>>> Hi
>>>>
>>>> On Wednesday 05 January 2005 23:12, Nico Sabbi wrote:
>>>>
>>>>
>>>>> Michael Niedermayer wrote:
>>>>>
>>>>>
>>>>>> Hi
>>>>>>
>>>>>> On Wednesday 05 January 2005 22:09, Nico Sabbi wrote:
>>>>>>
>>>>>>
>>>>>>> Hi,
>>>>>>> this patch permits to determine automatically the initial fps of
>>>>>>> mpeg4
>>>>>>> video in the VOL header,
>>>>>>> so there's no need to specify it with -fps.
>>>>>>>
>>>>>>> Michael, can you please check it?
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> did u try it with a few different framerates like a 24000/1001
>>>>>> .m4v stream
>>>>>> generated by ffmpeg? i doubt it will work
>>>>>>
>>>>>> [...]
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> I checked some fancy fps but not the fractional ones; now I see they
>>>>> aren't recognized
>>>>> correctly.
>>>>> If I understand correctly the specs the fixed_timeinc is given by the
>>>>> smallest
>>>>> number of bits (up to 16) to represent timeinc_resolution-1,
>>>>> correct ?
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>> IIRC, yes
>>>>
>>>>
>>>>
>>>>
>>>>> What's wrong? :)
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>> many mpeg4 files have no fixed_timeinc
>>>> [...]
>>>>
>>>>
>>>
>>> This one works correctly with all fps I tried, both with lavc and
>>> with xvid, in raw files and in TS.
>>> Is it ok ?
>>>
>>> Nico
>>
>>
>>
>>
>> sorry, this doesn't work with b-frames :(
>> next time ...
>>
>
> given that 3 consecutive frames are always enough to determine the
> smallest delta_timeinc
> (or I'm mistaken?) this patch should work correctly (it does for me,
> even seeking with -sb).
> Michael, what's your opinion?
>
>------------------------------------------------------------------------
>
>Index: mpeg_hdr.c
>===================================================================
>RCS file: /cvsroot/mplayer/main/libmpdemux/mpeg_hdr.c,v
>retrieving revision 1.5
>diff -c -u -r1.5 mpeg_hdr.c
>--- mpeg_hdr.c 3 Jul 2004 11:38:56 -0000 1.5
>+++ mpeg_hdr.c 7 Jan 2005 09:04:21 -0000
>@@ -27,7 +27,7 @@
> int width, height;
>
> if ((buffer[6] & 0x20) != 0x20){
>- printf("missing marker bit!\n");
>+ fprintf(stderr, "missing marker bit!\n");
> return 1; /* missing marker_bit */
> }
>
>@@ -101,3 +101,112 @@
> return 0;
> }
>
>+
>+//MPEG4 HEADERS
>+static unsigned char getbits(unsigned char *buffer, unsigned int from, unsigned char len)
>+{
>+ unsigned int n;
>+ unsigned char m, u, l, y;
>+
>+ n = from / 8;
>+ m = from % 8;
>+ u = 8 - m;
>+ l = (len > u ? len - u : 0);
>+
>+ y = (buffer[n] << m);
>+ if(8 > len)
>+ y >>= (8-len);
>+ if(l)
>+ y |= (buffer[n+1] >> (8-l));
>+
>+ //fprintf(stderr, "GETBITS(%d -> %d): bytes=0x%x 0x%x, n=%d, m=%d, l=%d, u=%d, Y=%d\n",
>+ // from, (int) len, (int) buffer[n],(int) buffer[n+1], n, (int) m, (int) l, (int) u, (int) y);
>+ return y;
>+}
>+
>+static int read_timeinc(mp_mpeg_header_t * picture, unsigned char * buffer, int n)
>+{
>+ if(picture->timeinc_bits > 8) {
>+ picture->timeinc_unit = getbits(buffer, n, picture->timeinc_bits - 8) << 8;
>+ n += picture->timeinc_bits - 8;
>+ picture->timeinc_unit |= getbits(buffer, n, 8);
>+ n += 8;
>+ } else {
>+ picture->timeinc_unit = getbits(buffer, n, picture->timeinc_bits);
>+ n += picture->timeinc_bits;
>+ }
>+ //fprintf(stderr, "TIMEINC2: %d, bits: %d\n", picture->timeinc_unit, picture->timeinc_bits);
>+ return n;
>+}
>+
>+int mp4_header_process_vol(mp_mpeg_header_t * picture, unsigned char * buffer)
>+{
>+ unsigned int n, aspect=0, aspectw=0, aspecth=0, x=1, v;
>+
>+ //begins with 0x0000012x
>+ picture->fps = 0;
>+ picture->timeinc_bits = picture->timeinc_resolution = picture->timeinc_unit = 0;
>+ n = 9;
>+ if(getbits(buffer, n, 1))
>+ n += 7;
>+ n++;
>+ aspect=getbits(buffer, n, 4);
>+ n += 4;
>+ if(aspect == 0x0f) {
>+ aspectw = getbits(buffer, n, 8);
>+ n += 8;
>+ aspecth = getbits(buffer, n, 8);
>+ n += 8;
>+ }
>+
>+ if(getbits(buffer, n, 1)) {
>+ n += 4;
>+ if(getbits(buffer, n, 1))
>+ n += 79;
>+ n++;
>+ } else n++;
>+
>+ n+=3;
>+
>+ picture->timeinc_resolution = getbits(buffer, n, 8) << 8;
>+ n += 8;
>+ picture->timeinc_resolution |= getbits(buffer, n, 8);
>+ n += 8;
>+
>+ picture->timeinc_bits = 0;
>+ v = picture->timeinc_resolution - 1;
>+ while(v && (x<16)) {
>+ v>>=1;
>+ picture->timeinc_bits++;
>+ }
>+ picture->timeinc_bits = (picture->timeinc_bits > 1 ? picture->timeinc_bits : 1);
>+
>+ n++; //marker bit
>+
>+ if(getbits(buffer, n, 1)) { //fixed_vop_timeinc
>+ n++;
>+ n = read_timeinc(picture, buffer, n);
>+
>+ if(picture->timeinc_unit)
>+ picture->fps = (picture->timeinc_resolution * 10000) / picture->timeinc_unit;
>+ }
>+
>+ //fprintf(stderr, "ASPECT: %d, PARW=%d, PARH=%d, TIMEINCRESOLUTION: %d, FIXED_TIMEINC: %d (number of bits: %d), FPS: %u\n",
>+ // aspect, aspectw, aspecth, picture->timeinc_resolution, picture->timeinc_unit, picture->timeinc_bits, picture->fps);
>+
>+ return 0;
>+}
>+
>+int mp4_header_process_vop(mp_mpeg_header_t * picture, unsigned char * buffer)
>+{
>+ int n;
>+ n = 0;
>+ picture->picture_type = getbits(buffer, n, 2);
>+ n += 2;
>+ while(getbits(buffer, n, 1))
>+ n++;
>+ n++;
>+ getbits(buffer, n, 1);
>+ n++;
>+ n = read_timeinc(picture, buffer, n);
>+}
>Index: mpeg_hdr.h
>===================================================================
>RCS file: /cvsroot/mplayer/main/libmpdemux/mpeg_hdr.h,v
>retrieving revision 1.1
>diff -c -u -r1.1 mpeg_hdr.h
>--- mpeg_hdr.h 30 Oct 2001 18:45:54 -0000 1.1
>+++ mpeg_hdr.h 7 Jan 2005 09:04:21 -0000
>@@ -15,7 +15,11 @@
> int progressive_frame;
> int top_field_first;
> int display_time; // secs*100
>+ //the following are for mpeg4
>+ int timeinc_resolution, timeinc_bits, timeinc_unit;
>+ int picture_type;
> } mp_mpeg_header_t;
>
> int mp_header_process_sequence_header (mp_mpeg_header_t * picture, unsigned char * buffer);
> int mp_header_process_extension (mp_mpeg_header_t * picture, unsigned char * buffer);
>+int mp4_header_process_vol(mp_mpeg_header_t * picture, unsigned char * buffer);
>Index: video.c
>===================================================================
>RCS file: /cvsroot/mplayer/main/libmpdemux/video.c,v
>retrieving revision 1.47
>diff -c -u -r1.47 video.c
>--- video.c 24 Nov 2004 18:55:03 -0000 1.47
>+++ video.c 7 Jan 2005 09:04:21 -0000
>@@ -116,6 +116,7 @@
> break;
> }
> case VIDEO_MPEG4: {
>+ int pos = 0, vop_cnt=0, units[3];
> videobuf_len=0; videobuf_code_len=0;
> mp_msg(MSGT_DECVIDEO,MSGL_V,"Searching for Video Object Start code... ");fflush(stdout);
> while(1){
>@@ -142,7 +143,14 @@
> return 0;
> }
> }
>- mp_msg(MSGT_DECVIDEO,MSGL_V,"OK!\nSearching for Video Object Plane Start code... ");fflush(stdout);
>+ pos = videobuf_len+4;
>+ if(!read_video_packet(d_video)){
>+ mp_msg(MSGT_DECVIDEO,MSGL_ERR,"Can't read Video Object Layer Header\n");
>+ return 0;
>+ }
>+ mp4_header_process_vol(&picture, &(videobuffer[pos]));
>+ mp_msg(MSGT_DECVIDEO,MSGL_V,"OK! FPS SEEMS TO BE %.3f\nSearching for Video Object Plane Start code... ", sh_video->fps);fflush(stdout);
>+ mp4_init:
> while(1){
> int i=sync_video_packet(d_video);
> if(i==0x1B6) break; // found it!
>@@ -151,6 +159,48 @@
> return 0;
> }
> }
>+ pos = videobuf_len+4;
>+ if(!read_video_packet(d_video)){
>+ mp_msg(MSGT_DECVIDEO,MSGL_ERR,"Can't read Video Object Plane Header\n");
>+ return 0;
>+ }
>+ mp4_header_process_vop(&picture, &(videobuffer[pos]));
>+ units[vop_cnt] = picture.timeinc_unit;
>+ vop_cnt++;
>+ //mp_msg(MSGT_DECVIDEO,MSGL_V, "TYPE: %d, unit: %d\n", picture.picture_type, picture.timeinc_unit);
>+ if(!picture.fps) {
>+ int i, mn, md, mx, diff;
>+ if(vop_cnt < 3)
>+ goto mp4_init;
>+
>+ i=0;
>+ mn = mx = units[0];
>+ for(i=0; i<3; i++) {
>+ if(units[i] < mn)
>+ mn = units[i];
>+ if(units[i] > mx)
>+ mx = units[i];
>+ }
>+ md = mn;
>+ for(i=0; i<3; i++) {
>+ if((units[i] > mn) && (units[i] < mx))
>+ md = units[i];
>+ }
>+ mp_msg(MSGT_DECVIDEO,MSGL_V, "MIN: %d, mid: %d, max: %d\n", mn, md, mx);
>+ if(mx - md > md - mn)
>+ diff = md - mn;
>+ else
>+ diff = mx - md;
>+ if(diff > 0){
>+ picture.fps = (picture.timeinc_resolution * 10000) / (diff);
>+ mp_msg(MSGT_DECVIDEO,MSGL_V, "FPS seems to be: %d/10000, resolution: %d, delta_units: %d\n", picture.fps, picture.timeinc_resolution, diff);
>+ }
>+ }
>+ if(picture.fps) {
>+ sh_video->fps=picture.fps*0.0001f;
>+ sh_video->frametime=10000.0f/(float)picture.fps;
>+ mp_msg(MSGT_DECVIDEO,MSGL_INFO, "FPS seems to be: %d/10000\n", picture.fps);
>+ }
> mp_msg(MSGT_DECVIDEO,MSGL_V,"OK!\n");
> sh_video->format=0x10000004;
> break;
>
>
>------------------------------------------------------------------------
>
>
>
Michael, any comment on this patch or should I consider it rejected?
In this last case what other method can you advise?
Thanks,
Nico
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