<div dir="ltr"><div><div><div>Hi, </div>Yes its constant bit-rate control, that work better that existing for me. I realize it's inside avcenc.c . I have not delved into driver sources, so may be worth to do something like that in driver. </div>Best Regards, </div>Warp.</div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Aug 21, 2014 at 4:48 AM, Zhao, Yakui <<a href="mailto:yakui.zhao@intel.com" target="_blank">yakui.zhao@intel.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wed, 2014-08-20 at 16:38 +0400, Alexey wrote: > Hi all, > > Hi, Alexey What is the purpose of your patch? I guees that it is for the Bit-rate control? If it is for constant bit-rate control, I don't think that it is necessary to put it in the avcenc test-case as the constant bit-rate control is done in low-level driver. Maybe it looks more reasonable that it is put into the driver. Thanks. Yakui <div class="HOEnZb"><div class="h5"> > I decided that problem with small modify avcenc.c . After each encoded > frame i do : > > enc->needsize = ( enc->frame_bit_rate * 1024 ) / 8; > if ( *outlen ) { > float o = (float)( (float)*outlen) / ( (float)enc->needsize / > (float)enc->fps ); > if ( o > 1.0f ) { > enc->slice_qp_delta_next += 2; > } else if ( o < 0.9f ){ > enc->slice_qp_delta_next--; > } > if ( enc->slice_qp_delta_next < -33 ) enc->slice_qp_delta_next = > -33; > if ( enc->slice_qp_delta_next > 17 ) enc->slice_qp_delta_next = > 17; > } > > > *outlen its size of current encoded frame. > > > > And in void avcenc_update_slice_parameter(struct h264_vaapi_enc *enc, > int slice_type) i set slice_param->slice_qp_delta = > enc->slice_qp_delta; > > > Initial qp value enc->qp_value = 33; > > > > Best Regards, > > Warp. > > > > On Tue, Aug 19, 2014 at 7:09 PM, Chris Healy <<a href="mailto:cphealy@gmail.com">cphealy@gmail.com</a>> > wrote: > Hi Zhao, > > > Thanks for pointing out the QP adjustment logic. I made the > (bad) assumption previously that it would be in gen7_mfc.c. > > I will file a bug and make a YUV stream available in the > coming days. > > Thanks, > > > Chris > > > > On Mon, Aug 18, 2014 at 6:03 PM, Zhao, Yakui > <<a href="mailto:yakui.zhao@intel.com">yakui.zhao@intel.com</a>> wrote: > On Mon, 2014-08-18 at 11:19 -0600, Chris Healy wrote: > > Well after taking a look at the behaviour again this > morning, (it was > > real late for me last night), it does seem that this > change did not > > solve the issue. I'm still seeing the same > inconsistent frame rate. > > > > The encoder still seems to be trying to average > things over a 20 > > second window. > > > > > > Where is the code that implements the per frame > adjustment of the QP? > > avcenc.c seems to just be responsible for setting up > some encoder > > preferences but does not do any dynamic QP > adjustment. Also, how can > > I enable some debugging to see what the QP is set to > for each frame? > > > > > > > Hi, Chris > > The QP adjustment is implemented in the function > of > intel_mfc_brc_postpack in gen6_mfc_common.c. (Sorry > that there is no > debug option to control whether the QP is printed for > every frame. You > can print the corresponding QP). > > Will you please help to create one bug in > <a href="https://bugs.freedesktop.org/" target="_blank">https://bugs.freedesktop.org/</a> and then attach your > original YUV stream? > Then we can look at the issue. > > Thanks. > Yakui > > > > > > On Mon, Aug 18, 2014 at 6:27 AM, Gwenole Beauchesne > > <<a href="mailto:gb.devel@gmail.com">gb.devel@gmail.com</a>> wrote: > > Hi Chris, > > > > 2014-08-18 11:55 GMT+02:00 Chris Healy > <<a href="mailto:cphealy@gmail.com">cphealy@gmail.com</a>>: > > > Hi Zhao, > > > > > > I just tested the new values you gave me. > This is a night > > and day > > > improvement in bitrate consistency. Based > on the small > > amount of testing I > > > have done, this seems to completely > address the problem! > > > > > > I have to understand why moving from 15 > and 900 to 1 and 60 > > makes the > > > bitrate so consistent. Both pairs of > values are the same so > > given the > > > following comment: /* Tc = > num_units_in_tick / time_sacle > > */ I have the > > > same Tc in both cases. > > > > > > This should make zero difference. If it > does, there should > > some arith > > error around, that needs to be investigated. > 900/15 or 60/1 > > still > > yield 30 fps. > > > > Note: a tick is the minimum time slice that > can be represented > > in the > > coded data. Typically, a field. time_scale > is the frequency. > > > > > How is this changing things for the better > AND, what is the > > tradeoff in > > > using these values. (There must be some > downside otherwise > > these values > > > would have always been 1 and 2 * fps.) > > > > > > Regards, > > > > > > Chris > > > > > > (PS - Thank you!) > > > > > > > > > On Mon, Aug 18, 2014 at 1:36 AM, Chris > Healy > > <<a href="mailto:cphealy@gmail.com">cphealy@gmail.com</a>> wrote: > > >> > > >> Hi Zhao, > > >> > > >> I've done testing with both 30 and 24 fps > and received > > similar results. > > >> > > >> I will test with the values you > mentioned. Can you explain > > how > > >> num_units_in_tick and time_scale work? > (What is a tick?) > > >> > > >> Also, is there a good place in the Intel > driver to dump the > > QP value used > > >> for each frame? I'd like to add some QP > logging when an > > env variable is > > >> set. > > >> > > >> Regards, > > >> > > >> Chris > > >> > > >> > > >> On Mon, Aug 18, 2014 at 1:30 AM, Zhao, > Yakui > > <<a href="mailto:yakui.zhao@intel.com">yakui.zhao@intel.com</a>> wrote: > > >>> > > >>> On Mon, 2014-08-18 at 01:13 -0600, Chris > Healy wrote: > > >>> > Hi Zhao, > > >>> > > > >>> > > > >>> > I enabled LIBVA_TRACE recently and > grabbed a bunch of > > output. Here's > > >>> > a link to good size fragment of the > output: > > >>> > > > >>> > <a href="http://pastebin.com/KJYzGQAA" target="_blank">http://pastebin.com/KJYzGQAA</a> > > >>> > > > >>> > > > >>> > Here's answers to the specific > questions you asked: > > (From LIBVA_TRACE > > >>> > output) > > >>> > > > >>> > [57113.237423] intra_period = 30 > > >>> > [57113.237424] intra_idr_period = 30 > > >>> > [57113.237425] ip_period = 1 > > >>> > [57113.237427] bits_per_second = > 3700000 > > >>> > [57113.237428] max_num_ref_frames = 2 > > >>> > [57113.237469] num_units_in_tick = 15 > > >>> > [57113.237470] time_scale = 900 > > >>> > > >>> If the expected fps is 24, the setting > of > > num_units_in_tick/time_scale > > >>> is incorrect. It will be better that you > should use the > > following > > >>> setting in your tool: > > >>> num_units_in_tick = 1 > > >>> time_scale = 2 * fps > > >>> > > >>> > > >>> > > >>> > > > >>> > I see avenc.c, but it's unclear to me > if I am dealing > > with an issue > > >>> > with the encoder application or > something lower down in > > libva or > > >>> > libva-driver-intel or the HW itself. > > >>> > > > >>> > > > >>> > Am I correct in believing (simplified) > that the HW is > > just given a raw > > >>> > video frame and a QP and the HW > returns a chunk of > > encoded data that > > >>> > is "some size" and that it is the > responsibility of the > > SW above the > > >>> > HW to dynamically adjust the QP to hit > the target > > bitrate to meet > > >>> > whatever the rate control algorithm > deems correct? > > >>> > > > >>> > > >>> When the CBR mode is used, the driver > will adjust QP > > dynamically so that > > >>> the encoded bitrate can meet with the > requirement of > > target bitrate > > >>> based on the input encoding > parameter(For example: > > intra_period, > > >>> ip_period, time_scale, num_units_in_tick > and so on). > > >>> > > >>> > > >>> > If this is the case, where is the code > that is > > dynamically adjusting > > >>> > the QP? Also, in the HW, where are > the registers and > > bits control the > > >>> > QP? (I'm looking at the "Intel ® > OpenSource HD Graphics > > Programmer’s > > >>> > Reference Manual (PRM) Volume 2 Part > 3: Multi-Format > > Transcoder – MFX > > >>> > (Ivy Bridge)" so a reference to the > registers might be > > helpful for me > > >>> > to understand better.) > > >>> > > > >>> > > > >>> > Regards, > > >>> > > > >>> > Chris > > >>> > > > >>> > > > >>> > > > >>> > On Sun, Aug 17, 2014 at 11:58 PM, > Zhao, Yakui > > <<a href="mailto:yakui.zhao@intel.com">yakui.zhao@intel.com</a>> > > >>> > wrote: > > >>> > On Sun, 2014-08-17 at 19:27 > -0600, Chris Healy > > wrote: > > >>> > > I've done some further > analysis with our real > > stream and we > > >>> > experience > > >>> > > the same inconsistent > bitrate behaviour as > > with the test > > >>> > app. It > > >>> > > seems to me that the way the > bitrate control > > works doesn't > > >>> > do a good > > >>> > > job of handling certain > input video sequences > > and the > > >>> > encoded bitrate > > >>> > > subsequently spikes as a > result of this. > > >>> > > > > >>> > > To help understand what I'm > dealing with, I've > > posted a > > >>> > video on > > >>> > > youtube showing the video > being encoded: > > >>> > > > > >>> > > > <a href="http://www.youtube.com/watch?v=LpYS_9IB0jU" target="_blank">www.youtube.com/watch?v=LpYS_9IB0jU</a> > > >>> > > > > >>> > > > > >>> > > I've also posted a bitrate > graph online too > > that shows what > > >>> > happens > > >>> > > when encoding the video > referenced above: > > >>> > > > > >>> > > <a href="http://snag.gy/imvBe.jpg" target="_blank">http://snag.gy/imvBe.jpg</a> > > >>> > > > > >>> > > > > >>> > > In the above graph, I set > the targeted encode > > bitrate to > > >>> > 3.7Mbps, CBR, > > >>> > > and High Profile H.264. > Most of the time the > > bitrate hovers > > >>> > around > > >>> > > 3.7Mbps, but sometimes the > bitrate drops very > > low then > > >>> > spikes up very > > >>> > > high. I also notice that > when the bitrate > > drops down low > > >>> > then spikes > > >>> > > up real high, the "highness" > seems to be a > > function of how > > >>> > much and > > >>> > > long the bitrate was under > 3.7Mbps. It seems > > that the rate > > >>> > control > > >>> > > logic is taking a 20 second > running bitrate > > average and > > >>> > trying it's > > >>> > > best to keep the aggregate > bitrate at 3.7Mbps, > > so if the > > >>> > scene > > >>> > > complexity drops, the rate > control logic > > reacts by cranking > > >>> > the QP to > > >>> > > a very low value (high > quality) to bring the > > bitrate back > > >>> > up. This > > >>> > > behaviour combined with the > fact that the > > video goes to a > > >>> > simple fixed > > >>> > > image, then crossfades to > something complex in > > less than 20 > > >>> > seconds > > >>> > > when the QP is a very low > value results in the > > massive spike > > >>> > in > > >>> > > bitrate. (This is my naive > understanding of > > what’s going > > >>> > on.) > > >>> > > > > >>> > > The code I'm using to encode > and stream is > > based in large > > >>> > part on > > >>> > > > libva/test/encode/h264encode.c. I'm not sure > > if the logic > > >>> > for doing > > >>> > > rate control is in libva, > libva-driver-intel, > > or supposed to > > >>> > be driven > > >>> > > by the code that uses libva. > Am I dealing > > with an issue > > >>> > with the > > >>> > > encoder itself or is it more > likely my code > > not correctly > > >>> > driving the > > >>> > > encoder? > > >>> > > > >>> > > > >>> > Hi, Chris > > >>> > > > >>> > Thank you for reporting > the issue. > > >>> > Will you please check the > encoding > > parameters required by > > >>> > CBR? (For > > >>> > example: > intra_period/ip_period/ > > >>> > > num_units_in_tick/time_scale/bits_per_second in > > >>> > > VAEncSequenceParameterBufferH264.) > > >>> > > > >>> > Will you please take a > look at the example > > of > > >>> > libva/test/encode/avcenc.c and > see whether it is > > helpful? > > >>> > (There exist two h264 encoding > examples because > > of history > > >>> > reasons. The > > >>> > avcenc case is more consistent > with the > > libva-intel-driver.) > > >>> > > > >>> > Thanks. > > >>> > Yakui > > >>> > > > >>> > > What can be changed to keep > the actual bitrate > > from being so > > >>> > bursty > > >>> > > given the video behaviour? > > >>> > > > > >>> > > > > >>> > > Regards, > > >>> > > > > >>> > > Chris > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > > > >>> > > On Fri, Aug 15, 2014 at 6:03 > PM, Chris Healy > > >>> > <<a href="mailto:cphealy@gmail.com">cphealy@gmail.com</a>> > > >>> > > wrote: > > >>> > > I've been encoding > h264 content using > > HD 4000 HW and > > >>> > am not > > >>> > > able to make heads > or tails of the way > > the encoder > > >>> > is behaving > > >>> > > from the standpoint > of the data size > > coming out of > > >>> > the > > >>> > > encoder. > > >>> > > > > >>> > > I have a 24 fps 720p > video that is the > > same image > > >>> > for ~8 > > >>> > > seconds, then a 1.5 > second fade to the > > next image > > >>> > followed by > > >>> > > another ~8 seconds > on that image. > > This goes on and > > >>> > on > > >>> > > indefinitely. I > would have expected > > that the > > >>> > bitrate would > > >>> > > have been pretty > low, then spike for > > 1.5 seconds > > >>> > then go back > > >>> > > to a similarly low > value. > > >>> > > > > >>> > > > > >>> > > When I look at the > data coming out of > > the encoder > > >>> > with a 4Mb/s > > >>> > > bitrate set and CBR, > I'm seeing almost > > the inverse > > >>> > where most > > >>> > > of the time, the > bitrate is pretty > > close to 4Mb/s > > >>> > then it > > >>> > > spikes above 4Mb/s > (presumably for the > > fade), then > > >>> > it drops > > >>> > > down to ~2Mbps for a > second or so > > before going back > > >>> > up to > > >>> > > ~4Mb/s. > > >>> > > > > >>> > > The strangest part > is that for the > > first ~30 seconds > > >>> > of > > >>> > > encode, across the > board, the bitrate > > is ~2x the > > >>> > bitrate from > > >>> > > second 31 -> end of > encode. (So, I'm > > hitting a > > >>> > typical rate > > >>> > > of 7Mbps and peaking > out at 13Mbps.) > > >>> > > > > >>> > > > > >>> > > Is this behaviour > expected with gen7 > > HW? Is there > > >>> > something I > > >>> > > can do in the > initial setup that will > > cap the MAX > > >>> > bitrate > > >>> > > regardless of the > impact on encode > > quality? > > >>> > > > > >>> > > Regards, > > >>> > > > > >>> > > Chris > > >>> > > > > >>> > > > > >>> > > > > >>> > > > >>> > > > >>> > > > >>> > > > >>> > > > >>> > > >>> > > >> > > > > > > > > > > > > _______________________________________________ > > > Libva mailing list > > > <a href="mailto:Libva@lists.freedesktop.org">Libva@lists.freedesktop.org</a> > > > > <a href="http://lists.freedesktop.org/mailman/listinfo/libva" target="_blank">http://lists.freedesktop.org/mailman/listinfo/libva</a> > > > > > > > > > Regards, > > -- > > Gwenole Beauchesne > > Intel Corporation SAS / 2 rue de Paris, > 92196 Meudon Cedex, > > France > > Registration Number (RCS): Nanterre B 302 > 456 199 > > > > > > > > > > > _______________________________________________ > Libva mailing list > <a href="mailto:Libva@lists.freedesktop.org">Libva@lists.freedesktop.org</a> > <a href="http://lists.freedesktop.org/mailman/listinfo/libva" target="_blank">http://lists.freedesktop.org/mailman/listinfo/libva</a> > > > > _______________________________________________ > Libva mailing list > <a href="mailto:Libva@lists.freedesktop.org">Libva@lists.freedesktop.org</a> > <a href="http://lists.freedesktop.org/mailman/listinfo/libva" target="_blank">http://lists.freedesktop.org/mailman/listinfo/libva</a> </div></div></blockquote></div> </div>