On Saturday, December 18, 2021, Terje J. Hanssen via Cin < [email protected]> wrote:
> > > Den 17.12.2021 15:00, skrev Terje J. Hanssen: > >> >> Den 17.12.2021 04:58, skrev Andrew Randrianasulu: >> >>> >>> >>> On Friday, December 17, 2021, Terje J. Hanssen <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> [......] >> >>> =============== >>> >>> I-frame-only 50 Megabit MPEG-2 or comparable DV50 in 4:2:2 as >>> high-end, "visually lossless" intermediate format for archival and >>> suited for editing? >>> >>> ----------------- >>> >>> Regarding DV50, FFMpeg has a friendly "target dv50" support >>> (similar as "target DVD"). So to get a first look on a DV50 test >>> file, I simply transcoded 422/10bit Video and PCM audio from a MOV >>> file (ProRes 422HQ) to a raw DV50 (422/8bit) file: >>> >>> ffmpeg -i SD-MOV.mov -target pal-dv50 SD-DV50.dv >>> >>> [......] >>> >>> >> 205M SD-DV50.dv (ffmpeg re-encoded/remuxed) AV-info: >>> >>> avprobe SD-DV50.dv >>> avprobe version 12.3, Copyright (c) 2007-2018 the Libav developers >>> built on Mar 26 2018 12:39 with gcc 11 (SUSE Linux) >>> [dv @ 0x55cdddb96440] Estimating duration from bitrate, this may >>> be inaccurate >>> Input #0, dv, from 'SD-DV50.dv': >>> Metadata: >>> timecode : 00:00:00:00 >>> Duration: 00:00:29.80, start: 0.000000, bitrate: 57600 kb/s >>> Stream #0:0: Video: dvvideo, yuv422p, 720x576 [SAR 16:15 DAR >>> 4:3], 25000 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc >>> Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s >>> Stream #0:2: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s >>> # avprobe output >>> >>> =================== >>> >>> As seen above, it looks like ffmpeg produced wrong meta data for >>> the DV50 video bitrate (25 Mb/s=DV25), while the total bitrate >>> 57.6 Mb/s is correct. (Also similar was seen with ffprobe and >>> Mediainfo). >>> >>> My VLC player or Gnome movieplayer did not playback the DV50 file, >>> while ffplay did (as usual without audio?). >>> >>> Cin-GG miss a DV50 preset among format setting. However DV50 else >>> loades preliminary OK in Cin-GG (via ffmpeg). >>> >>> >>> I'll look at dv50 output preset.. >>> >>> Fine >> >> =============== > > I tried also to transcode and remux 422 Video and PCM Audio to a 50 Mbps > MPEG-2 I-frame only program stream. > > 1) MPG From MOV (ProRes 422HQ) > ------------------------------ > > ffmpeg -i SD-MOV.mov -c:v mpeg2video -bf 2 -b:v 50M -maxrate 50M -minrate > 50M -c:a pcm_s16be -f vob SD-MP2I-50.mpg > [....] > Stream mapping: > Stream #0:0 -> #0:0 (prores (native) -> mpeg2video (native)) > Stream #0:1 -> #0:1 (pcm_s24le (native) -> pcm_s16be (native)) > Press [q] to stop, [?] for help > [mpeg2video @ 0x560ffd164ec0] Automatically choosing VBV buffer size of > 746 kbyte > [vob @ 0x560ffd14d180] At most 8 channels allowed for LPCM streams. > Could not write header for output file #0 (incorrect codec parameters ?): > Invalid argument > Error initializing output stream 0:1 -- > > ***This failed because PreRes Audio uses 16 channels:*** yeah... interesting limitation.. and interesting number of channels.. > > ffprobe SD-MOV.mov 2>&1 >/dev/null | grep Stream.*Audio > Stream #0:1(eng): Audio: pcm_s24le (lpcm / 0x6D63706C), 48000 Hz, 16 > channels, s32 (24 bit), 18432 kb/s (default) > > > 2) MPG from DV50 > ---------------- > ffmpeg -i SD-DV50.dv -c:v mpeg2video -bf 2 -b:v 50M -maxrate 50M -minrate > 50M -c:a pcm_s16be -f vob SD-MP2I-50.mpg > > du -sh * > 205M SD-DV50.dv > 284M SD-MOV.mov > 186M SD-MP2I-50.mpg > > avprobe SD-MP2I-50.mpg > Input #0, mpeg, from 'SD-MP2I-50.mpg': > Duration: 00:00:29.77, start: 0.540000, bitrate: 52167 kb/s > Stream #0:0[0x1e0]: Video: mpeg2video (4:2:2), yuv422p(tv, > progressive), 720x576 [SAR 16:15 DAR 4:3], 50000 kb/s, 25 fps, 25 tbr, 90k > tbn, 50 tbc > Stream #0:1[0xa0]: Audio: pcm_dvd, 48000 Hz, 2 channels, s16, 1536 kb/s > > ***** The SD-MP2I-50.mpg file size is here 90% of DV50 ******** > > The SD-MP2I-50.mpg playback ok with VLC, Gnome movieplayer, ffplay, and > loads and playback in Cin-GG > The audio volume seems low (weak), but can probably be adjusted higher > with ffmpeg > > well, but I missed keyframe parameter? bitrate is big but I think without special param ffmpeg still will not make all-I mpeg2 stream..? ------------------------- > > Terje J. H > > > > > > > > > > > > > > > > > > > > > > > -- > Cin mailing list > [email protected] > https://lists.cinelerra-gg.org/mailman/listinfo/cin >
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