Gregleto
25th October 2013, 20:07
Is it possible to create an encode with one reference frame using main or high profiles? If yes, how can we query a file to determine how many reference frames it actually uses? I know this sounds like a ridiculously obvious question, but our experience seems to be telling us something different.
Using two different front-ends (Handbrake and Telestream Vantage) we are creating x264 encodes, setting reference frames to “1” and querying them with MediInfo. In each case, setting the Profile to Main or High and setting reference frames to “1” always provides conflicting information in MediaInfo. The MediaInfo field labeled “Format settings, ReFrames” always reports “2”, while the “Encoding Settings” field reports “ref=1” (see below). Using the Baseline profile, both fields report the correct number of “1”.
Assuming both of these fields are reporting the number of reference frames in the video, we have no obvious way to tell what was actually used… ref=1 or ref=2.
Am I confused?
Thanks,
Gregleto
General
Complete name : C:\Users\Greg Letourneau\Desktop\10-25-13 Production encoding changes\redorbit_test_new_specs_HANDBRAKE.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 15.5 MiB
Duration : 4mn 24s
Overall bit rate mode : Variable
Overall bit rate : 491 Kbps
Encoded date : UTC 2013-10-25 16:24:52
Tagged date : UTC 2013-10-25 16:28:43
Writing application : HandBrake 0.9.9 2013051800
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 4mn 24s
Bit rate mode : Variable
Bit rate : 378 Kbps
Width : 640 pixels
Height : 360 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 29.970 fps
Minimum frame rate : 9.990 fps
Maximum frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.055
Stream size : 11.9 MiB (77%)
Writing library : x264 core 130 r2273 b3065e6
Encoding settings : cabac=1 / ref=1 / deblock=1:-1:-1 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=3 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=24.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=14000 / vbv_bufsize=14000 / crf_max=0.0 / nal_hrd=none / ip_ratio=1.40 / aq=1:1.00
Encoded date : UTC 2013-10-25 16:24:52
Tagged date : UTC 2013-10-25 16:28:43
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Using two different front-ends (Handbrake and Telestream Vantage) we are creating x264 encodes, setting reference frames to “1” and querying them with MediInfo. In each case, setting the Profile to Main or High and setting reference frames to “1” always provides conflicting information in MediaInfo. The MediaInfo field labeled “Format settings, ReFrames” always reports “2”, while the “Encoding Settings” field reports “ref=1” (see below). Using the Baseline profile, both fields report the correct number of “1”.
Assuming both of these fields are reporting the number of reference frames in the video, we have no obvious way to tell what was actually used… ref=1 or ref=2.
Am I confused?
Thanks,
Gregleto
General
Complete name : C:\Users\Greg Letourneau\Desktop\10-25-13 Production encoding changes\redorbit_test_new_specs_HANDBRAKE.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 15.5 MiB
Duration : 4mn 24s
Overall bit rate mode : Variable
Overall bit rate : 491 Kbps
Encoded date : UTC 2013-10-25 16:24:52
Tagged date : UTC 2013-10-25 16:28:43
Writing application : HandBrake 0.9.9 2013051800
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 4mn 24s
Bit rate mode : Variable
Bit rate : 378 Kbps
Width : 640 pixels
Height : 360 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 29.970 fps
Minimum frame rate : 9.990 fps
Maximum frame rate : 29.970 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.055
Stream size : 11.9 MiB (77%)
Writing library : x264 core 130 r2273 b3065e6
Encoding settings : cabac=1 / ref=1 / deblock=1:-1:-1 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=3 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=30 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=24.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=14000 / vbv_bufsize=14000 / crf_max=0.0 / nal_hrd=none / ip_ratio=1.40 / aq=1:1.00
Encoded date : UTC 2013-10-25 16:24:52
Tagged date : UTC 2013-10-25 16:28:43
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709