[FFmpeg-devel] [PATCH] fix raw FLAC muxer extradata handling
Michael Niedermayer
michaelni
Sun Feb 22 14:15:03 CET 2009
On Sat, Feb 21, 2009 at 09:25:45PM -0500, Justin Ruggles wrote:
> Michael Niedermayer wrote:
> > On Sat, Feb 21, 2009 at 04:27:54PM -0500, Justin Ruggles wrote:
> >> Michael Niedermayer wrote:
> >>> On Fri, Feb 20, 2009 at 08:57:09PM -0500, Justin Ruggles wrote:
> >>>> Michael Niedermayer wrote:
> >>>>> On Sun, Feb 15, 2009 at 07:41:26PM -0500, Justin Ruggles wrote:
> >>>>>> Michael Niedermayer wrote:
> >>>>>>> On Thu, Feb 12, 2009 at 10:07:52PM -0500, Justin Ruggles wrote:
> >>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>> On Thu, Feb 12, 2009 at 08:06:25PM -0500, Justin Ruggles wrote:
> >>>>>>>>>> Michael Niedermayer wrote:
> >>>>>>>>>>> On Thu, Feb 12, 2009 at 07:26:33PM -0500, Justin Ruggles wrote:
> >>>>>>>>>>>> Hi,
> >>>>>>>>>>>>
> >>>>>>>>>>>> This patch makes it so the raw FLAC muxer supports either full header or
> >>>>>>>>>>>> STREAMINFO-only extradata. It fixes support for converting FLAC-in-MKV
> >>>>>>>>>>>> to raw FLAC using -acodec copy.
> >>>>>>>>>>>>
> >>>>>>>>>>>> -Justin
> >>>>>>>>>>>>
> >>>>>>>>>>>> Index: libavformat/raw.c
> >>>>>>>>>>>> ===================================================================
> >>>>>>>>>>>> --- libavformat/raw.c (revision 17188)
> >>>>>>>>>>>> +++ libavformat/raw.c (working copy)
> >>>>>>>>>>>> @@ -24,6 +24,7 @@
> >>>>>>>>>>>> #include "libavcodec/ac3_parser.h"
> >>>>>>>>>>>> #include "libavcodec/bitstream.h"
> >>>>>>>>>>>> #include "libavcodec/bytestream.h"
> >>>>>>>>>>>> +#include "libavcodec/flac.h"
> >>>>>>>>>>>> #include "avformat.h"
> >>>>>>>>>>>> #include "raw.h"
> >>>>>>>>>>>> #include "id3v2.h"
> >>>>>>>>>>>> @@ -37,8 +38,12 @@
> >>>>>>>>>>>> };
> >>>>>>>>>>>> uint8_t *streaminfo = s->streams[0]->codec->extradata;
> >>>>>>>>>>>> int len = s->streams[0]->codec->extradata_size;
> >>>>>>>>>>>> - if(streaminfo != NULL && len > 0) {
> >>>>>>>>>>>> - put_buffer(s->pb, header, 8);
> >>>>>>>>>>>> + if (streaminfo != NULL && len >= FLAC_STREAMINFO_SIZE) {
> >>>>>>>>>>>> + if (len == FLAC_STREAMINFO_SIZE) {
> >>>>>>>>>>>> + put_buffer(s->pb, header, 8);
> >>>>>>>>>>>> + } else if (AV_RL32(streaminfo) != MKTAG('f','L','a','C') || len < 8+FLAC_STREAMINFO_SIZE) {
> >>>>>>>>>>>> + return 0;
> >>>>>>>>>>> for which case is this?
> >>>>>>>>>> Case when extradata does not contain only STREAMINFO, nor a valid header.
> >>>>>>>>> I didnt mean that ..
> >>>>>>>>> my question was more in what case, as in "a file from foogar" ...
> >>>>>>>>> also considering this hypothetical case, what would the code do?
> >>>>>>>>> imean not (return 0) but rather
> >>>>>>>>> create valid flac, create invalid file, print error?
> >>>>>>>> point taken. this would silently create invalid files for incorrectly
> >>>>>>>> formatted or wrong length extradata, whether from the user or from an
> >>>>>>>> invalid input file.
> >>>>>>>>
> >>>>>>>>>>> also the whole does not look particularely robust, i mean an extra byte at the
> >>>>>>>>>>> end will make it fail silently, it would be different if there was an error
> >>>>>>>>>>> message ...
> >>>>>>>>>> I see your point. An alternative solution would be to only check for
> >>>>>>>>>> "fLaC" and not extradata_size to determine the format of the extradata.
> >>>>>>>>>> The size checks could be done in each branch to just ensure minimum
> >>>>>>>>>> sizes. I can also add an error message and error return value for
> >>>>>>>>>> invalid extradata. If that sounds better I can submit a new patch shortly.
> >>>>>>>>> The key goal i have is
> >>>>>>>>> * do not generate invalid files, at least not without a huge warning
> >>>>>>>>> * when it fails it should do so with noise to asist bug analysis and debuging
> >>>>>>>>> * simple, clean, fast, readable (you know, the big goals of every programmer ...)
> >>>>>>>> new patch attached.
> >>>>>>>>
> >>>>>>>> For flac_write_header(), it fails with an error message and returns an
> >>>>>>>> error value when there is no extradata or if it is too short since such
> >>>>>>>> cases would always create an invalid file. It allows for the
> >>>>>>>> hypothetical case you gave where the extradata is STREAMINFO plus some
> >>>>>>>> extra unneeded bytes, but prints a warning message and still creates a
> >>>>>>>> valid file if the first 34 bytes are valid.
> >>>>>>>>
> >>>>>>>> For flac_write_trailer(), no error is returned for too short or missing
> >>>>>>>> metadata since rewriting the STREAMINFO is not necessary for a valid
> >>>>>>>> FLAC file. A warning message is printed in such cases though.
> >>>>>>>>
> >>>>>>>> -Justin
> >>>>>>>>
> >>>>>>>> Index: libavformat/raw.c
> >>>>>>>> ===================================================================
> >>>>>>>> --- libavformat/raw.c (revision 17188)
> >>>>>>>> +++ libavformat/raw.c (working copy)
> >>>>>>>> @@ -24,6 +24,7 @@
> >>>>>>>> #include "libavcodec/ac3_parser.h"
> >>>>>>>> #include "libavcodec/bitstream.h"
> >>>>>>>> #include "libavcodec/bytestream.h"
> >>>>>>>> +#include "libavcodec/flac.h"
> >>>>>>>> #include "avformat.h"
> >>>>>>>> #include "raw.h"
> >>>>>>>> #include "id3v2.h"
> >>>>>>>> @@ -37,9 +38,23 @@
> >>>>>>>> };
> >>>>>>>> uint8_t *streaminfo = s->streams[0]->codec->extradata;
> >>>>>>>> int len = s->streams[0]->codec->extradata_size;
> >>>>>>>> - if(streaminfo != NULL && len > 0) {
> >>>>>>>> + if (streaminfo != NULL && len >= FLAC_STREAMINFO_SIZE) {
> >>>>>>>> + if (AV_RL32(streaminfo) != MKTAG('f','L','a','C')) {
> >>>>>>>> + /* extradata contains STREAMINFO only */
> >>>>>>>> + if (len != FLAC_STREAMINFO_SIZE) {
> >>>>>>>> + av_log(s, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
> >>>>>>>> + FLAC_STREAMINFO_SIZE-len);
> >>>>>>>> + }
> >>>>>>>> put_buffer(s->pb, header, 8);
> >>>>>>>> + len = FLAC_STREAMINFO_SIZE;
> >>>>>>>> + } else if (len < 8+FLAC_STREAMINFO_SIZE) {
> >>>>>>>> + av_log(s, AV_LOG_ERROR, "extradata too small.\n");
> >>>>>>>> + return -1;
> >>>>>>>> + }
> >>>>>>>> put_buffer(s->pb, streaminfo, len);
> >>>>>>>> + } else {
> >>>>>>>> + av_log(s, AV_LOG_ERROR, "extradata not found or too small.\n");
> >>>>>>>> + return -1;
> >>>>>>>> }
> >>>>>>>> return 0;
> >>>>>>>> }
> >>>>>>>> @@ -51,12 +66,23 @@
> >>>>>>>> int len = s->streams[0]->codec->extradata_size;
> >>>>>>>> int64_t file_size;
> >>>>>>>>
> >>>>>>>> - if (streaminfo && len > 0 && !url_is_streamed(s->pb)) {
> >>>>>>>> + if (streaminfo && len >= FLAC_STREAMINFO_SIZE && !url_is_streamed(s->pb)) {
> >>>>>>> how can the first 2 conditions be false here?
> >>>>>> User sets NULL or too small extradata. Our encoder would never do this.
> >>>>>> And stream copy should fail at write_header() in such cases (although it
> >>>>>> does not currently). But if the user does something stupid, this
> >>>>>> prevents trying to write to the extradata if it's NULL or too small.
> >>>>>> We
> >>>>>> cannot rely on the extradata not changing between write_header() and
> >>>>>> write_trailer() correct?
> >>>>> extradata should generally not change, there are some rare cases like
> >>>>> updating some frame count or so where it might because it cant be
> >>>>> done the other way around easily but in general no extradata should
> >>>>> not change and especially not significatly
> >>>>>
> >>>>>
> >>>>>>> also i dont see how the code here really can be considered a step toward
> >>>>>>> a solution.
> >>>>>>> flac can be stored in many containers, we cannot duplicate these checks in
> >>>>>>> every. ogg_build_flac_headers() being just one spot where this stuff is
> >>>>>>> needed as well
> >>>>>> I did not notice before you brought it up, but ogg_build_flac_headers()
> >>>>>> needs to be changed as well, as it currently does not support full
> >>>>>> header extradata. Matroska supports either type, but only checks the
> >>>>>> extradata_size, not the "fLaC" signature. AFAIK, the rest that support
> >>>>>> FLAC just write all the extradata as-is.
> >>>>>>
> >>>>>> What do you think about a shared function such as:
> >>>>>>
> >>>>>> enum {
> >>>>>> FLAC_EXTRADATA_FORMAT_STREAMINFO = 0,
> >>>>>> FLAC_EXTRADATA_FORMAT_FULL_HEADER = 1
> >>>>>> }
> >>>>>> /**
> >>>>>> * Validate FLAC extradata.
> >>>>>> * @param[out] format format of the extradata.
> >>>>>> * @param[out] streaminfo_start pointer in extradata to
> >>>>>> * start of STREAMINFO.
> >>>>>> * @return zero for success, non-zero for error.
> >>>>>> */
> >>>>>> int ff_flac_validate_extradata(uint8_t *extradata,
> >>>>> ff_is_extradata_valid()
> >>>>> makes the return meaning obvious and thus means no need to read the doxy
> >>>>>
> >>>>> and i like the idea
> >>>> Patch set attached.
> >>>>
> >>>> [PATCH 1/5] Use a shared function to validate FLAC extradata.
> >>>> [PATCH 2/5] Add support for full header extradata to raw FLAC muxer.
> >>>> [PATCH 3/5] cosmetics: add a comment in flac_write_header().
> >>>> [PATCH 4/5] Share the function to write a raw FLAC header and use in the
> >>>> Matroska muxer.
> >>>> [PATCH 5/5] cosmetics: line wrap and indentation
> >>>>
> >>>> Thanks,
> >>>> Justin
> >>>>
> >> New patches attached. I did not attach the cosmetic patches this time or
> >> PATCH 2/5 which was already approved.
> >>
> >>>> diff --git a/libavcodec/flac.h b/libavcodec/flac.h
> >>>> index 9a4f820..3dabf07 100644
> >>>> --- a/libavcodec/flac.h
> >>>> +++ b/libavcodec/flac.h
> >>>> @@ -42,6 +42,11 @@ enum {
> >>>> FLAC_METADATA_TYPE_INVALID = 127
> >>>> };
> >>>>
> >>>> +enum {
> >>>> + FLAC_EXTRADATA_FORMAT_STREAMINFO = 0,
> >>>> + FLAC_EXTRADATA_FORMAT_FULL_HEADER = 1
> >>>> +};
> >>>> +
> >>>> /**
> >>>> * Data needed from the Streaminfo header for use by the raw FLAC demuxer
> >>>> * and/or the FLAC decoder.
> >>>
> >>>> @@ -68,4 +73,14 @@ typedef struct FLACStreaminfo {
> >>>> void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
> >>>> const uint8_t *buffer);
> >>>>
> >>>> +/**
> >>>> + * Validate the FLAC extradata.
> >>>> + * @param[in] avctx codec context containing the extradata.
> >>>> + * @param[out] format extradata format.
> >>>> + * @param[out] streaminfo_start pointer to start of 34-byte STREAMINFO data.
> >>>> + * @return 1 if valid, 0 if not valid.
> >>>> + */
> >>>> +int ff_flac_is_extradata_valid(AVCodecContext *avctx, int *format,
> >>> ^^^
> >>> enum
> >> fixed.
> >>
> >>> [...]
> >>>> diff --git a/libavformat/oggenc.c b/libavformat/oggenc.c
> >>> [...]
> >>> not maintained by me
> >> Baptiste?
> >>
> >>>> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> >>>> index 25f20fc..f0c8f57 100644
> >>>> --- a/libavformat/matroskaenc.c
> >>>> +++ b/libavformat/matroskaenc.c
> >>> not maintained by me
> >> Aurel, I updated the last patch to remove the inclusion of flac.h and
> >> add dependencies on raw.o to matroska_muxer and matroska_audio_muxer.
> >>
> >> I moved ff_flac_write_header() to inside of CONFIG_FLAC_MUXER so that
> >> all the other (de)muxers in raw.o don't depend on libavcodec/flacdec.o.
> >> Due to that change, I also updated configure for matroska_muxer and
> >> matroska_audio_muxer to depend on flac_muxer.
> >>
> >> Thanks,
> >> Justin
> >>
> >>
> >
> > [...]
> >> --- a/libavformat/raw.c
> >> +++ b/libavformat/raw.c
> >> @@ -31,12 +31,11 @@
> >>
> >> /* simple formats */
> >> #if CONFIG_FLAC_MUXER
> >> -static int flac_write_header(struct AVFormatContext *s)
> >> +int ff_flac_write_header(ByteIOContext *pb, AVCodecContext *codec)
> >> {
> >
> > i doubt a little that this belongs on raw.c/h
>
> True, it would definitely make dependencies simpler if it were split it
> into a separate file. How about libavformat/flac.[ch]?
ok
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
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