encoding - 使用 FFMPEG 对 HLS 进行编码会导致 DTS 降低

Question

我正在尝试为 HTS 实时流编码视频，但在使用 Apple Media Validator (mediastreamvalidator) 验证流时遇到问题。（我的测试文件：http ://dominicansinteractive.idoms.org/media/9536/playlist.m3u8 ）

输出是：

--------------------------------------------------------------------------------
http://dominicansinteractive.idoms.org/media/9536/199/prog_index.m3u8
--------------------------------------------------------------------------------

Playlist Validation: 

    OK

Segments:

segment_00000.ts:

    ERROR: (-1) Decreasing DTS were detected in track 0
    ERROR: (-1) Decreasing DTS were detected in track 1

    Average segment duration: 8.07 seconds
    Average segment bitrate: 2155094.67 bps
    Average segment structural overhead: 206525.83 bps (9.58 %)

第二段似乎没有问题：

[mpegts @ 0x1d78120] Format mpegts probed with size=2048 and score=100
[mpegts @ 0x1d78120] stream=0 stream_type=1b pid=100 prog_reg_desc=
[mpegts @ 0x1d78120] stream=1 stream_type=f pid=101 prog_reg_desc=
[mpegts @ 0x1d78120] File position before avformat_find_stream_info() is 0
[h264 @ 0x1d7c1c0] Current profile doesn't provide more RBSP data in PPS, skipping
[h264 @ 0x1d7c1c0] no picture 
[h264 @ 0x1d7c1c0] Current profile doesn't provide more RBSP data in PPS, skipping
   Last message repeated 3 times
[mpegts @ 0x1d78120] max_analyze_duration 5000000 reached at 5013333
[mpegts @ 0x1d78120] File position after avformat_find_stream_info() is 0

对于 HLS 来说，这似乎是一个严重的问题，所以我正在寻找是否有办法解决这个问题。

在我得到的编码文件中查看 FFMPEG 时（电子邮件底部的编码器输出/命令）：

ffmpeg -loglevel 99 -i encoded.ts 
ffmpeg version N-37783-gdf3a96c Copyright (c) 2000-2012 the FFmpeg developers
 built on Jul  4 2012 07:44:52 with gcc 4.4.5
 configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libvpx --enable-libfaac --enable-nonfree
 libavutil      51. 63.100 / 51. 63.100
 libavcodec     54. 32.100 / 54. 32.100
 libavformat    54. 14.100 / 54. 14.100
 libavdevice    54.  0.100 / 54.  0.100
 libavfilter     3.  0.101 /  3.  0.101
 libswscale      2.  1.100 /  2.  1.100
 libswresample   0. 15.100 /  0. 15.100
 libpostproc    52.  0.100 / 52.  0.100
[mpegts @ 0x2023120] Format mpegts probed with size=2048 and score=100
[mpegts @ 0x2023120] stream=0 stream_type=1b pid=100 prog_reg_desc=
[mpegts @ 0x2023120] stream=1 stream_type=f pid=101 prog_reg_desc=
[mpegts @ 0x2023120] File position before avformat_find_stream_info() is 0
[h264 @ 0x20271c0] Current profile doesn't provide more RBSP data in PPS, skipping
[h264 @ 0x20271c0] no picture 
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 143280 in que
   Last message repeated 6 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 158640 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 175920 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 193200 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 210480 in que
   Last message repeated 7 times
[h264 @ 0x20271c0] Current profile doesn't provide more RBSP data in PPS, skipping
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 227760 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 245040 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 262320 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 279600 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 296880 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 314160 in que
   Last message repeated 7 times
[h264 @ 0x20271c0] Current profile doesn't provide more RBSP data in PPS, skipping
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 331440 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 348720 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 366000 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 383280 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 400560 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 417840 in que
   Last message repeated 6 times
[h264 @ 0x20271c0] Current profile doesn't provide more RBSP data in PPS, skipping
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 433200 in que
   Last message repeated 6 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 448560 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 465840 in que
   Last message repeated 6 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 481200 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 498480 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 515760 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 533040 in que
   Last message repeated 6 times
[h264 @ 0x20271c0] Current profile doesn't provide more RBSP data in PPS, skipping
[mpegts @ 0x2023120] first_dts 124080 not matching first dts 548400 in que
   Last message repeated 7 times
[mpegts @ 0x2023120] max_analyze_duration 5000000 reached at 5000000
[mpegts @ 0x2023120] File position after avformat_find_stream_info() is 0

And when at the first segmented file:
ffmpeg -loglevel 99 -i segment_00000.ts 
ffmpeg version N-37783-gdf3a96c Copyright (c) 2000-2012 the FFmpeg developers
 built on Jul  4 2012 07:44:52 with gcc 4.4.5
 configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libvpx --enable-libfaac --enable-nonfree
 libavutil      51. 63.100 / 51. 63.100
 libavcodec     54. 32.100 / 54. 32.100
 libavformat    54. 14.100 / 54. 14.100
 libavdevice    54.  0.100 / 54.  0.100
 libavfilter     3.  0.101 /  3.  0.101
 libswscale      2.  1.100 /  2.  1.100
 libswresample   0. 15.100 /  0. 15.100
 libpostproc    52.  0.100 / 52.  0.100
[mpegts @ 0x1a0b120] Format mpegts probed with size=2048 and score=100
[mpegts @ 0x1a0b120] stream=0 stream_type=1b pid=100 prog_reg_desc=
[mpegts @ 0x1a0b120] stream=1 stream_type=f pid=101 prog_reg_desc=
[mpegts @ 0x1a0b120] File position before avformat_find_stream_info() is 0
[mpegts @ 0x1a0b120] Invalid timestamps stream=0, pts=1920, dts=8589929312, size=2355
[mpegts @ 0x1a0b120] Invalid timestamps stream=0, pts=16320, dts=8589932912, size=3203
[h264 @ 0x1a0f1c0] Current profile doesn't provide more RBSP data in PPS, skipping
[h264 @ 0x1a0f1c0] no picture 
[h264 @ 0x1a0f1c0] Current profile doesn't provide more RBSP data in PPS, skipping
   Last message repeated 3 times
[mpegts @ 0x1a0b120] max_analyze_duration 5000000 reached at 5013333
[mpegts @ 0x1a0b120] File position after avformat_find_stream_info() is 0

BASELINE 配置文件不会出现此问题，但 MAIN 会出现此问题。

我用于编码的命令是：

ffmpeg, -i, [path]/test.mov, -y, -f, mpegts, -acodec, aac, -strict, -2, -ar, 48000, -b:a, 128000, -s, 960x540, -vcodec, libx264, -b:v, 1200000, -aspect, 960:540, -r, 25, -level, 3.1, -vprofile, main, -flags, +loop, -cmp, +chroma, -partitions, +parti4x4+partp8x8+partb8x8, -subq, 5, -trellis, 1, -refs, 1, -coder, 0, -me_range, 16, -keyint_min, 25, -sc_threshold, 40, -i_qfactor, 0.71, -bt, 200k, -maxrate, 1200000, -bufsize, 1200000, -rc_eq, 'blurCplx^(1-qComp)', -qcomp, 0.6, -qmin, 10, -qmax, 51, -qdiff, 4, -level, 30, -g, 30, -async, 2, [path]/encoded.ts

08:40:29,843 DEBUG ~ FFMPEG(1):   libavutil      51. 63.100 / 51. 63.100
08:40:29,843 DEBUG ~ FFMPEG(1):   libavcodec     54. 32.100 / 54. 32.100
08:40:29,843 DEBUG ~ FFMPEG(1):   libavformat    54. 14.100 / 54. 14.100
08:40:29,843 DEBUG ~ FFMPEG(1):   libavdevice    54.  0.100 / 54.  0.100
08:40:29,843 DEBUG ~ FFMPEG(1):   libavfilter     3.  0.101 /  3.  0.101
08:40:29,844 DEBUG ~ FFMPEG(1):   libswscale      2.  1.100 /  2.  1.100
08:40:29,844 DEBUG ~ FFMPEG(1):   libswresample   0. 15.100 /  0. 15.100
08:40:29,844 DEBUG ~ FFMPEG(1):   libpostproc    52.  0.100 / 52.  0.100
08:40:30,033 DEBUG ~ FFMPEG(1): Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '[path]/test.mov':
08:40:30,033 DEBUG ~ FFMPEG(1):   Metadata:
08:40:30,033 DEBUG ~ FFMPEG(1):     major_brand     : qt  
08:40:30,033 DEBUG ~ FFMPEG(1):     minor_version   : 537199360
08:40:30,035 DEBUG ~ FFMPEG(1):     compatible_brands: qt  
08:40:30,035 DEBUG ~ FFMPEG(1):     creation_time   : 2011-12-05 10:54:24
08:40:30,036 DEBUG ~ FFMPEG(1):     timecode        : 00:00:00:00
08:40:30,036 DEBUG ~ FFMPEG(1):   Duration: 00:00:24.20, start: 0.000000, bitrate: 9912 kb/s
08:40:30,037 DEBUG ~ FFMPEG(1):     Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080, 9777 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
08:40:30,037 DEBUG ~ FFMPEG(1):     Metadata:
08:40:30,037 DEBUG ~ FFMPEG(1):       creation_time   : 2011-12-05 10:56:28
08:40:30,037 DEBUG ~ FFMPEG(1):       handler_name    : Apple Video Media Handler
08:40:30,038 DEBUG ~ FFMPEG(1):     Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 129 kb/s
08:40:30,038 DEBUG ~ FFMPEG(1):     Metadata:
08:40:30,038 DEBUG ~ FFMPEG(1):       creation_time   : 2011-12-05 10:56:28
08:40:30,038 DEBUG ~ FFMPEG(1):       handler_name    : Apple Sound Media Handler
08:40:30,038 DEBUG ~ FFMPEG(1):     Stream #0:2(eng): Data: none (tmcd / 0x64636D74)
08:40:30,038 DEBUG ~ FFMPEG(1):     Metadata:
08:40:30,038 DEBUG ~ FFMPEG(1):       creation_time   : 2011-12-05 10:56:28
08:40:30,039 DEBUG ~ FFMPEG(1):       handler_name    : Time Code Media Handler
08:40:30,039 DEBUG ~ FFMPEG(1):       timecode        : 00:00:00:00
08:40:30,092 DEBUG ~ FFMPEG(1): [graph 0 input from stream 0:0 @ 0x1c17180] w:1920 h:1080 pixfmt:yuv420p tb:1/25 fr:25/1 sar:0/1 sws_param:flags=2
08:40:30,092 DEBUG ~ FFMPEG(1): [output stream 0:0 @ 0x1c033a0] No opaque field provided
08:40:30,110 DEBUG ~ FFMPEG(1): [scaler for output stream 0:0 @ 0x1c18040] w:1920 h:1080 fmt:yuv420p sar:0/1 -> w:960 h:540 fmt:yuv420p sar:0/1 flags:0x4
08:40:30,110 DEBUG ~ FFMPEG(1): [graph 1 input from stream 0:1 @ 0x1c53440] tb:1/48000 samplefmt:s16 samplerate:48000 chlayout:0x3
08:40:30,110 DEBUG ~ FFMPEG(1): -async is forwarded to lavfi similarly to -af aresample=min_comp=0.001:min_hard_comp=0.100000:max_soft_comp=0.000042.
08:40:30,122 DEBUG ~ FFMPEG(1): [graph 1 aresample for input stream 0:1 @ 0x1c36880] chl:stereo fmt:s16 r:48000Hz -> chl:stereo fmt:flt r:48000Hz
08:40:30,142 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] using SAR=1/1
08:40:30,142 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] frame MB size (60x34) > level limit (1620)
08:40:30,142 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] DPB size (4 frames, 3133440 bytes) > level limit (3 frames, 3110400 bytes)
08:40:30,142 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] MB rate (51000) > level limit (40500)
08:40:30,170 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] using cpu capabilities: MMX2 SSE2Slow SlowCTZ
08:40:30,182 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] profile Main, level 3.0
08:40:30,235 DEBUG ~ FFMPEG(1): [mpegts @ 0x1be3540] muxrate VBR, pcr every 2 pkts, sdt every 200, pat/pmt every 40 pkts
08:40:30,235 DEBUG ~ FFMPEG(1): Output #0, mpegts, to '[path]/encoded.ts':
08:40:30,235 DEBUG ~ FFMPEG(1):   Metadata:
08:40:30,235 DEBUG ~ FFMPEG(1):     major_brand     : qt  
08:40:30,235 DEBUG ~ FFMPEG(1):     minor_version   : 537199360
08:40:30,235 DEBUG ~ FFMPEG(1):     compatible_brands: qt  
08:40:30,235 DEBUG ~ FFMPEG(1):     timecode        : 00:00:00:00
08:40:30,235 DEBUG ~ FFMPEG(1):     encoder         : Lavf54.14.100
08:40:30,235 DEBUG ~ FFMPEG(1):     Stream #0:0(eng): Video: h264, yuv420p, 960x540 [SAR 1:1 DAR 16:9], q=10-51, 1200 kb/s, 90k tbn, 25 tbc
08:40:30,235 DEBUG ~ FFMPEG(1):     Metadata:
08:40:30,235 DEBUG ~ FFMPEG(1):       creation_time   : 2011-12-05 10:56:28
08:40:30,235 DEBUG ~ FFMPEG(1):       handler_name    : Apple Video Media Handler
08:40:30,236 DEBUG ~ FFMPEG(1):     Stream #0:1(eng): Audio: aac, 48000 Hz, stereo, flt, 128 kb/s
08:40:30,236 DEBUG ~ FFMPEG(1):     Metadata:
08:40:30,236 DEBUG ~ FFMPEG(1):       creation_time   : 2011-12-05 10:56:28
08:40:30,236 DEBUG ~ FFMPEG(1):       handler_name    : Apple Sound Media Handler
08:40:30,236 DEBUG ~ FFMPEG(1): Stream mapping:
08:40:30,236 DEBUG ~ FFMPEG(1):   Stream #0:0 -> #0:0 (h264 -> libx264)
08:40:30,236 DEBUG ~ FFMPEG(1):   Stream #0:1 -> #0:1 (aac -> aac)

[...]

08:40:55,398 DEBUG ~ FFMPEG(1): video:3121kB audio:359kB subtitle:0 global headers:0kB muxing overhead 11.132085%
08:40:55,407 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] frame I:21    Avg QP:21.57  size: 88153
08:40:55,407 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] frame P:233   Avg QP:22.74  size:  5560
08:40:55,407 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] frame B:351   Avg QP:27.45  size:   141
08:40:55,407 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] consecutive B-frames: 21.7%  2.0%  3.0% 73.4%
08:40:55,407 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] mb I  I16..4: 54.5%  0.0% 45.5%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] mb P  I16..4:  4.7%  0.0%  1.3%  P16..4: 24.6%  3.5%  0.8%  0.0%  0.0%    skip:65.1%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] mb B  I16..4:  0.1%  0.0%  0.1%  B16..8:  0.5%  0.1%  0.0%  direct: 0.6%  skip:98.6%  L0:32.3% L1:47.1% BI:20.6%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] coded y,uvDC,uvAC intra: 59.4% 5.8% 0.4% inter: 5.4% 3.0% 0.0%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] i16 v,h,dc,p: 58% 16% 21%  4%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 21% 17%  5% 10%  7%  5%  5% 10%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] i8c dc,h,v,p: 94%  3%  3%  0%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] Weighted P-Frames: Y:13.7% UV:3.4%
08:40:55,422 DEBUG ~ FFMPEG(1): [libx264 @ 0x1be3cc0] kb/s:1056.61

对于分段是：

ffmpeg, -i,[path]encoded.ts, -y, -c, copy, -flags, global_header, -map, 0, -f, segment, -segment_time, 10, -segment_list, [path]/fileList.txt, -segment_format, mpegts, [path]/segment_%05d.ts]

任何帮助将不胜感激！

score 4 · Accepted Answer

Apple Media Validator 报告的错误是合法的。其实TS文件是左右坏掉的。

问题文件 (segment_00000.ts) 在 PID 0x100 具有 H.264，在 0x0101 具有 AAC。PCR_PID 设置为 0x0100，即 AVC 流。

在文件偏移 564 处，它有以下 TS 数据包：

47 41 00 30 
07 50 FF FF F5 B0 7E 00 
00 00 01 E0 0D D8 80 C0 0A 31 00 01 0F 01 1F FF FF D6 C1 00

第二行是适应字段，表示 PCR = 2576978793600。第三行是 PES 数据包，表示 PTS = 576000 和 DTS = 2576978793600，频率为 27Mhz。

由于 PTS 与 PCR 相距甚远，我们可以说这个 TS 数据包已损坏。

以下 PCR 在文件偏移 9212 处发出信号，PCR 为 576000，PTS 为 2736000，DTS 为 576000。现在，我们有了这些观察结果。

PCR/PTS/DTS 现在有一些合理的值，但是......
与之前的 DTS 相比，这个新的 DTS 更早，因此 Apple Media Validator 会报错。
PCR 与 DTS 相同，表示 T-STD 下溢错误。

不幸的是，我不熟悉 ffmpeg，所以我不知道如何修复它。但是，仅通过查看此输出文件，我就感觉到使用中的 TS 多路复用器尚未达到最高质量。

score 1 · Accepted Answer

http://developer.android.com/guide/appendix/media-formats.html

推荐的所有视频质量的视频编解码器是 H.264 基线配置文件（这实际上很糟糕）所以可能是因为上述原因而建议的，或者更好地说，因为这些格式、内容等内部存在某种类型的不兼容。

score 0 · Accepted Answer

对于 HLS，您应该使用 hls 多路复用器 (-f hls)，而不是通用段多路复用器。通用段复用器并不真正生成与 HLS 兼容的 TS 文件。

encoding - 使用 FFMPEG 对 HLS 进行编码会导致 DTS 降低

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