[Ffmpeg-devel] corrupt audio when cut [SOLVED]
Cyrus A
lists
Tue Jan 23 19:03:48 CET 2007
Wolfram Gloger wrote:
> Hi,
>
>
>> I first got the most recent svn to my home directory. Then, I copied
>> the patch file to my home directory. I used the command "patch -p0 <
>> patch.diff" to apply the patch, then ran configure --enable-mp3lame and
>> then make.
>>
>
> That is correct if you intend to change sources in the 'trunk'
> directory, and configure and compile within the 'trunk' directory.
>
> Actually I missed adding a prototype for av_get_cur_dts as an exercise
> for the reader :-/. Sorry. Perhaps that is the reason for your
> continued problem?
>
> Augmented patch attached.
>
> Regards,
> Wolfram.
>
> diff -ur trunk/libavformat/avformat.h ffmpeg-wg/libavformat/avformat.h
> --- trunk/libavformat/avformat.h Sun Dec 24 11:06:34 2006
> +++ ffmpeg/libavformat/avformat.h Tue Jan 16 10:14:05 2007
> @@ -437,6 +437,8 @@
> int64_t pos, int64_t timestamp, int size, int distance, int flags);
> int av_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags);
> void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp);
> +/* current dts in AV_TIME_BASE units */
> +int64_t av_get_cur_dts(AVFormatContext *s, int stream_index);
> int64_t av_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts, int64_t pos_min, int64_t pos_max, int64_t pos_limit, int64_t ts_min, int64_t ts_max, int flags, int64_t *ts_ret, int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t ));
>
> /* media file output */
> diff -ur trunk/ffmpeg.c ffmpeg/ffmpeg.c
> --- trunk/ffmpeg.c Sat Jan 13 20:47:31 2007
> +++ ffmpeg/ffmpeg.c Tue Jan 16 10:46:51 2007
> @@ -2613,6 +2613,16 @@
> }
> /* reset seek info */
> start_time = 0;
> + if (av_get_cur_dts(ic, -1) != AV_NOPTS_VALUE) {
> + timestamp = av_get_cur_dts(ic, -1);
> + fprintf(stderr, "*** after seek timestamp= %lld\n", timestamp);
> + }
> + /* reload stream parameters */
> + ret = av_find_stream_info(ic);
> + if (ret < 0 && verbose >= 0) {
> + fprintf(stderr, "%s: could not find codec parameters\n", filename);
> + exit(1);
> + }
> }
>
> /* update the current parameters so that they match the one of the input stream */
> diff -ur trunk/libavformat/avidec.c ffmpeg/libavformat/avidec.c
> --- trunk/libavformat/avidec.c Tue Jan 16 09:34:41 2007
> +++ ffmpeg/libavformat/avidec.c Tue Jan 16 10:34:16 2007
> @@ -26,8 +26,8 @@
> #undef NDEBUG
> #include <assert.h>
>
> -//#define DEBUG
> -//#define DEBUG_SEEK
> +#define DEBUG
> +#define DEBUG_SEEK
>
> typedef struct AVIStream {
> int64_t frame_offset; /* current frame (video) or byte (audio) counter
> @@ -961,7 +961,7 @@
>
> // av_log(NULL, AV_LOG_DEBUG, "%"PRId64" %d %"PRId64"\n", timestamp, index, st2->index_entries[index].timestamp);
> /* extract the current frame number */
> - ast2->frame_offset = st2->index_entries[index].timestamp;
> + st2->cur_dts = ast2->frame_offset = st2->index_entries[index].timestamp;
> if(ast2->sample_size)
> ast2->frame_offset *=ast2->sample_size;
> }
> diff -ur trunk/libavformat/utils.c ffmpeg/libavformat/utils.c
> --- trunk/libavformat/utils.c Mon Jan 8 16:01:14 2007
> +++ ffmpeg/libavformat/utils.c Tue Jan 16 10:46:51 2007
> @@ -1437,6 +1437,27 @@
> return av_seek_frame_generic(s, stream_index, timestamp, flags);
> }
>
> +/**
> + * Obtain the current dts in AV_TIME_BASE units.
> + * @param stream_index If stream_index is (-1), a default
> + * stream is selected.
> + */
> +int64_t av_get_cur_dts(AVFormatContext *s, int stream_index)
> +{
> + AVStream *st;
> +
> + if (stream_index < 0){
> + stream_index= av_find_default_stream_index(s);
> + if(stream_index < 0)
> + return AV_NOPTS_VALUE;
> + }
> + st= s->streams[stream_index];
> + if (st->cur_dts == AV_NOPTS_VALUE)
> + return AV_NOPTS_VALUE;
> + return av_rescale(st->cur_dts, AV_TIME_BASE * (int64_t)st->time_base.num,
> + st->time_base.den);
> +}
> +
> /*******************************************************/
>
> /**
> @@ -1561,6 +1582,7 @@
> int read_size, i, ret;
> int64_t end_time;
> int64_t filesize, offset, duration;
> + offset_t old_offset;
>
> /* free previous packet */
> if (ic->cur_st && ic->cur_st->parser)
> @@ -1580,7 +1602,8 @@
>
> /* we read the first packets to get the first PTS (not fully
> accurate, but it is enough now) */
> - url_fseek(&ic->pb, 0, SEEK_SET);
> + old_offset = url_ftell(&ic->pb);
> + url_fseek(&ic->pb, 0, SEEK_CUR);
> read_size = 0;
> for(;;) {
> if (read_size >= DURATION_MAX_READ_SIZE)
> @@ -1646,7 +1669,7 @@
>
> fill_all_stream_timings(ic);
>
> - url_fseek(&ic->pb, 0, SEEK_SET);
> + url_fseek(&ic->pb, old_offset, SEEK_SET);
> }
>
> static void av_estimate_timings(AVFormatContext *ic)
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at mplayerhq.hu
> http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel
>
This patch worked for me, although there was some extra output during
the cutting process that didn't look normal:
/home/cyrus/ffmpeg/ffmpeg -ss 48.0 -t 25.8 -y -vcodec copy -acodec copy
-i test.avi cutfile.avi
FFmpeg version SVN-r7669, Copyright (c) 2000-2006 Fabrice Bellard, et al.
configuration: --enable-mp3lame
libavutil version: 49.2.0
libavcodec version: 51.29.0
libavformat version: 51.8.0
built on Jan 23 2007 12:43:45, gcc: 4.1.1 20060525 (Red Hat 4.1.1-1)
tag: tag=LIST size=0x2276
list: tag=hdrl size=0x0
tag: tag=avih size=0x38
tag: tag=LIST size=0x1090
list: tag=strl size=0x0
tag: tag=strh size=0x38
strh: tag=vids size=0xffffffff
tag: tag=strf size=0x28
video: tag=DX50 size=0x0
tag: tag=JUNK size=0x1014
tag: tag=LIST size=0x1086
list: tag=strl size=0x0
tag: tag=strh size=0x38
strh: tag=auds size=0xffffffff
tag: tag=strf size=0x1e
tag: tag=JUNK size=0x1014
tag: tag=JUNK size=0x104
tag: tag=LIST size=0x18
list: tag=INFO size=0x0
tag: tag=ISFT size=0xb
tag: tag=JUNK size=0x3f8
tag: tag=LIST size=0x51b94c
list: tag=movi size=0x0
movi end=51dffe
movi_end=0x51dffe
tag=idx1 size=0x16ad0
*** after seek timestamp= 47781067
Seems stream 0 codec frame rate differs from container frame rate:
30000.00 (30000/1) -> 29.97 (30000/1001)
Input #0, avi, from 'test.avi':
Duration: 00:01:25.0, start: 0.000000, bitrate: 513 kb/s
Stream #0.0: Video: mpeg4, yuv420p, 480x384, 29.97 fps(r)
Stream #0.1: Audio: mp3, 44100 Hz, stereo, 192 kb/s
Output #0, avi, to 'cutfile.avi':
Stream #0.0: Video: mpeg4, yuv420p, 480x384, q=2-31, 29.97 fps(c)
Stream #0.1: Audio: mp3, 44100 Hz, stereo, 192 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Stream #0.1 -> #0.1
Press [q] to stop encoding
frame= 774 q=0.0 Lsize= 1445kB time=25.8 bitrate= 458.8kbits/s
video:789kB audio:604kB global headers:0kB muxing overhead 3.754022%
Aside from that debugging output, it worked fine. Can we add this patch
to the main development branch so that future versions have the fix?
Cyrus
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