[FFmpeg-devel,3/3] lavf/sdp: add more thorough error handling

Return error codes when constructing a stream config fails, rather than
just disregarding the failure and continuing.
Propagate the error codes from av_sdp_create().
---
 libavformat/internal.h |   7 +-
 libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
 2 files changed, 120 insertions(+), 76 deletions(-)

On Sat, Dec 04, 2021 at 06:33:00PM +0100, Anton Khirnov wrote:
> Return error codes when constructing a stream config fails, rather than
> just disregarding the failure and continuing.
> Propagate the error codes from av_sdp_create().
> ---
>  libavformat/internal.h |   7 +-
>  libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
>  2 files changed, 120 insertions(+), 76 deletions(-)
> 
> diff --git a/libavformat/internal.h b/libavformat/internal.h
> index 528ff7e017..db1d83be17 100644
> --- a/libavformat/internal.h
> +++ b/libavformat/internal.h
> @@ -545,10 +545,11 @@ uint64_t ff_parse_ntp_time(uint64_t ntp_ts);
>   * @param ttl the time to live of the stream, 0 if not multicast
>   * @param fmt the AVFormatContext, which might contain options modifying
>   *            the generated SDP
> + * @return 0 on success, a negative error code on failure
>   */
> -void ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> -                        const char *dest_addr, const char *dest_type,
> -                        int port, int ttl, AVFormatContext *fmt);
> +int ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> +                       const char *dest_addr, const char *dest_type,
> +                       int port, int ttl, AVFormatContext *fmt);
>  

ff_sdp_write_media() is used by movenc.c also, maybe it's better to add the 
error check there also.

>  /**
>   * Write a packet to another muxer than the one the user originally
> diff --git a/libavformat/sdp.c b/libavformat/sdp.c
> index 1cdd21c97b..a5aba8a80c 100644
> --- a/libavformat/sdp.c
> +++ b/libavformat/sdp.c
> @@ -151,7 +151,8 @@ static int sdp_get_address(char *dest_addr, int size, int *ttl, const char *url)
>  }
>  
>  #define MAX_PSET_SIZE 1024
> -static char *extradata2psets(AVFormatContext *s, const AVCodecParameters *par)
> +static int extradata2psets(AVFormatContext *s, const AVCodecParameters *par,
> +                           char **out)
>  {
>      char *psets, *p;
>      const uint8_t *r;
> @@ -162,15 +163,18 @@ static char *extradata2psets(AVFormatContext *s, const AVCodecParameters *par)
>      uint8_t *tmpbuf = NULL;
>      const uint8_t *sps = NULL, *sps_end;
>  
> +    *out = NULL;
> +
>      if (par->extradata_size > MAX_EXTRADATA_SIZE) {
>          av_log(s, AV_LOG_ERROR, "Too much extradata!\n");
> -
> -        return NULL;
> +        return AVERROR_INVALIDDATA;
>      }
>      if (par->extradata[0] == 1) {
> -        if (ff_avc_write_annexb_extradata(par->extradata, &extradata,
> -                                          &extradata_size))
> -            return NULL;
> +        int ret = ff_avc_write_annexb_extradata(par->extradata, &extradata,
> +                                                &extradata_size);
> +        if (ret < 0)
> +            return ret;
> +
>          tmpbuf = extradata;
>      }
>  
> @@ -178,7 +182,7 @@ static char *extradata2psets(AVFormatContext *s, const AVCodecParameters *par)
>      if (!psets) {
>          av_log(s, AV_LOG_ERROR, "Cannot allocate memory for the parameter sets.\n");
>          av_free(tmpbuf);
> -        return NULL;
> +        return AVERROR(ENOMEM);
>      }
>      memcpy(psets, pset_string, strlen(pset_string));
>      p = psets + strlen(pset_string);
> @@ -203,11 +207,12 @@ static char *extradata2psets(AVFormatContext *s, const AVCodecParameters *par)
>              sps_end = r1;
>          }
>          if (!av_base64_encode(p, MAX_PSET_SIZE - (p - psets), r, r1 - r)) {
> -            av_log(s, AV_LOG_ERROR, "Cannot Base64-encode %"PTRDIFF_SPECIFIER" %"PTRDIFF_SPECIFIER"!\n", MAX_PSET_SIZE - (p - psets), r1 - r);
> +            av_log(s, AV_LOG_ERROR, "Cannot Base64-encode %"PTRDIFF_SPECIFIER" %"PTRDIFF_SPECIFIER"!\n",
> +                   MAX_PSET_SIZE - (p - psets), r1 - r);
>              av_free(psets);
>              av_free(tmpbuf);
>  
> -            return NULL;
> +            return AVERROR_INVALIDDATA;
>          }
>          p += strlen(p);
>          r = r1;
> @@ -220,10 +225,11 @@ static char *extradata2psets(AVFormatContext *s, const AVCodecParameters *par)
>      }
>      av_free(tmpbuf);
>  
> -    return psets;
> +    *out = psets;
> +    return 0;
>  }
>  
> -static char *extradata2psets_hevc(const AVCodecParameters *par)
> +static int extradata2psets_hevc(const AVCodecParameters *par, char **out)
>  {
>      char *psets;
>      uint8_t *extradata = par->extradata;
> @@ -232,7 +238,9 @@ static char *extradata2psets_hevc(const AVCodecParameters *par)
>      int ps_pos[3] = { 0 };
>      static const char * const ps_names[3] = { "vps", "sps", "pps" };
>      int num_arrays, num_nalus;
> -    int pos, i, j;
> +    int pos, i, j, ret;
> +
> +    *out = NULL;
>  
>      // Convert to hvcc format. Since we need to group multiple NALUs of
>      // the same type, and we might need to convert from one format to the
> @@ -240,9 +248,13 @@ static char *extradata2psets_hevc(const AVCodecParameters *par)
>      // format.
>      if (par->extradata[0] != 1) {
>          AVIOContext *pb;
> -        if (avio_open_dyn_buf(&pb) < 0)
> -            return NULL;
> -        if (ff_isom_write_hvcc(pb, par->extradata, par->extradata_size, 0) < 0) {
> +
> +        ret = avio_open_dyn_buf(&pb);
> +        if (ret < 0)
> +            return ret;
> +
> +        ret = ff_isom_write_hvcc(pb, par->extradata, par->extradata_size, 0);
> +        if (ret < 0) {
>              avio_close_dyn_buf(pb, &tmpbuf);
>              goto err;
>          }
> @@ -285,8 +297,11 @@ static char *extradata2psets_hevc(const AVCodecParameters *par)
>          goto err;
>  
>      psets = av_mallocz(MAX_PSET_SIZE);
> -    if (!psets)
> +    if (!psets) {
> +        ret = AVERROR(ENOMEM);
>          goto err;
> +    }
> +
>      psets[0] = '\0';
>  
>      for (i = 0; i < 3; i++) {
> @@ -317,41 +332,49 @@ static char *extradata2psets_hevc(const AVCodecParameters *par)
>      }
>      av_free(tmpbuf);
>  
> -    return psets;
> -
> +    *out = psets;
> +    return 0;
>  err:
> +    if (ret >= 0)
> +        ret = AVERROR_INVALIDDATA;
>      av_free(tmpbuf);
> -    return NULL;
> +    return ret;
>  }
>  
> -static char *extradata2config(AVFormatContext *s, const AVCodecParameters *par)
> +static int extradata2config(AVFormatContext *s, const AVCodecParameters *par,
> +                            char **out)
>  {
>      char *config;
>  
> +    *out = NULL;
> +
>      if (par->extradata_size > MAX_EXTRADATA_SIZE) {
>          av_log(s, AV_LOG_ERROR, "Too much extradata!\n");
> -
> -        return NULL;
> +        return AVERROR_INVALIDDATA;
>      }
>      config = av_malloc(10 + par->extradata_size * 2);
>      if (!config) {
>          av_log(s, AV_LOG_ERROR, "Cannot allocate memory for the config info.\n");
> -        return NULL;
> +        return AVERROR(ENOMEM);
>      }
>      memcpy(config, "; config=", 9);
>      ff_data_to_hex(config + 9, par->extradata, par->extradata_size, 0);
>      config[9 + par->extradata_size * 2] = 0;
>  
> -    return config;
> +    *out = config;
> +    return 0;
>  }
>  
> -static char *xiph_extradata2config(AVFormatContext *s, const AVCodecParameters *par)
> +static int xiph_extradata2config(AVFormatContext *s, const AVCodecParameters *par,
> +                                 char **out)
>  {
>      uint8_t *config;
>      char *encoded_config;
>      const uint8_t *header_start[3];
>      int headers_len, header_len[3], config_len;
> -    int first_header_size;
> +    int first_header_size, ret;
> +
> +    *out = NULL;
>  
>      switch (par->codec_id) {
>      case AV_CODEC_ID_THEORA:
> @@ -362,14 +385,15 @@ static char *xiph_extradata2config(AVFormatContext *s, const AVCodecParameters *
>          break;
>      default:
>          av_log(s, AV_LOG_ERROR, "Unsupported Xiph codec ID\n");
> -        return NULL;
> +        return AVERROR(ENOSYS);
>      }
>  
> -    if (avpriv_split_xiph_headers(par->extradata, par->extradata_size,
> -                              first_header_size, header_start,
> -                              header_len) < 0) {
> +    ret = avpriv_split_xiph_headers(par->extradata, par->extradata_size,
> +                                    first_header_size, header_start,
> +                                    header_len);
> +    if (ret < 0) {
>          av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
> -        return NULL;
> +        return ret;
>      }
>  
>      headers_len = header_len[0] + header_len[2];
> @@ -407,12 +431,13 @@ static char *xiph_extradata2config(AVFormatContext *s, const AVCodecParameters *
>                       config, config_len);
>      av_free(config);
>  
> -    return encoded_config;
> +    *out = encoded_config;
> +    return 0;
>  
>  xiph_fail:
>      av_log(s, AV_LOG_ERROR,
>             "Not enough memory for configuration string\n");
> -    return NULL;
> +    return AVERROR(ENOMEM);
>  }
>  
>  static int latm_context2profilelevel(const AVCodecParameters *par)
> @@ -444,7 +469,8 @@ static int latm_context2profilelevel(const AVCodecParameters *par)
>      return profile_level;
>  }
>  
> -static char *latm_context2config(AVFormatContext *s, const AVCodecParameters *par)
> +static int latm_context2config(AVFormatContext *s, const AVCodecParameters *par,
> +                               char **out)
>  {
>      /* MP4A-LATM
>       * The RTP payload format specification is described in RFC 3016
> @@ -454,12 +480,14 @@ static char *latm_context2config(AVFormatContext *s, const AVCodecParameters *pa
>      int rate_index;
>      char *config;
>  
> +    *out = NULL;
> +
>      for (rate_index = 0; rate_index < 16; rate_index++)
>          if (avpriv_mpeg4audio_sample_rates[rate_index] == par->sample_rate)
>              break;
>      if (rate_index == 16) {
>          av_log(s, AV_LOG_ERROR, "Unsupported sample rate\n");
> -        return NULL;
> +        return AVERROR(ENOSYS);
>      }
>  
>      config_byte[0] = 0x40;
> @@ -472,19 +500,21 @@ static char *latm_context2config(AVFormatContext *s, const AVCodecParameters *pa
>      config = av_malloc(6*2+1);
>      if (!config) {
>          av_log(s, AV_LOG_ERROR, "Cannot allocate memory for the config info.\n");
> -        return NULL;
> +        return AVERROR(ENOMEM);
>      }
>      ff_data_to_hex(config, config_byte, 6, 1);
>      config[12] = 0;
>  
> -    return config;
> +    *out = config;
> +    return 0;
>  }
>  
> -static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st,
> -                                        int payload_type, AVFormatContext *fmt)
> +static int sdp_write_media_attributes(char *buff, int size, const AVStream *st,
> +                                      int payload_type, AVFormatContext *fmt)
>  {
>      char *config = NULL;
>      const AVCodecParameters *p = st->codecpar;
> +    int ret = 0;
>  
>      switch (p->codec_id) {
>      case AV_CODEC_ID_DIRAC:
> @@ -496,7 +526,9 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>              av_opt_flag_is_set(fmt->priv_data, "rtpflags", "h264_mode0"))
>              mode = 0;
>          if (p->extradata_size) {
> -            config = extradata2psets(fmt, p);
> +            ret = extradata2psets(fmt, p, &config);
> +            if (ret < 0)
> +                return ret;
>          }
>          av_strlcatf(buff, size, "a=rtpmap:%d H264/90000\r\n"
>                                  "a=fmtp:%d packetization-mode=%d%s\r\n",
> @@ -533,8 +565,11 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>                                  payload_type, p->width, p->height);
>          break;
>      case AV_CODEC_ID_HEVC:
> -        if (p->extradata_size)
> -            config = extradata2psets_hevc(p);
> +        if (p->extradata_size) {
> +            ret = extradata2psets_hevc(p, &config);
> +            if (ret < 0)
> +                return ret;
> +        }
>          av_strlcatf(buff, size, "a=rtpmap:%d H265/90000\r\n", payload_type);
>          if (config)
>              av_strlcatf(buff, size, "a=fmtp:%d %s\r\n",
> @@ -542,7 +577,9 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>          break;
>      case AV_CODEC_ID_MPEG4:
>          if (p->extradata_size) {
> -            config = extradata2config(fmt, p);
> +            ret = extradata2config(fmt, p, &config);
> +            if (ret < 0)
> +                return ret;
>          }
>          av_strlcatf(buff, size, "a=rtpmap:%d MP4V-ES/90000\r\n"
>                                  "a=fmtp:%d profile-level-id=1%s\r\n",
> @@ -552,25 +589,24 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>      case AV_CODEC_ID_AAC:
>          if (fmt && fmt->oformat && fmt->oformat->priv_class &&
>              av_opt_flag_is_set(fmt->priv_data, "rtpflags", "latm")) {
> -            config = latm_context2config(fmt, p);
> -            if (!config)
> -                return NULL;
> +            ret = latm_context2config(fmt, p, &config);
> +            if (ret < 0)
> +                return ret;
>              av_strlcatf(buff, size, "a=rtpmap:%d MP4A-LATM/%d/%d\r\n"
>                                      "a=fmtp:%d profile-level-id=%d;cpresent=0;config=%s\r\n",
>                                       payload_type, p->sample_rate, p->channels,
>                                       payload_type, latm_context2profilelevel(p), config);
>          } else {
>              if (p->extradata_size) {
> -                config = extradata2config(fmt, p);
> +                ret = extradata2config(fmt, p, &config);
> +                if (ret < 0)
> +                    return ret;
>              } else {
>                  /* FIXME: maybe we can forge config information based on the
>                   *        codec parameters...
>                   */
>                  av_log(fmt, AV_LOG_ERROR, "AAC with no global headers is currently not supported.\n");
> -                return NULL;
> -            }
> -            if (!config) {
> -                return NULL;
> +                return AVERROR(ENOSYS);
>              }
>              av_strlcatf(buff, size, "a=rtpmap:%d MPEG4-GENERIC/%d/%d\r\n"
>                                      "a=fmtp:%d profile-level-id=1;"
> @@ -618,11 +654,13 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>          break;
>      case AV_CODEC_ID_VORBIS:
>          if (p->extradata_size)
> -            config = xiph_extradata2config(fmt, p);
> -        else
> +            ret = xiph_extradata2config(fmt, p, &config);
> +        else {
>              av_log(fmt, AV_LOG_ERROR, "Vorbis configuration info missing\n");
> -        if (!config)
> -            return NULL;
> +            ret = AVERROR_INVALIDDATA;
> +        }
> +        if (ret < 0)
> +            return ret;
>  
>          av_strlcatf(buff, size, "a=rtpmap:%d vorbis/%d/%d\r\n"
>                                  "a=fmtp:%d configuration=%s\r\n",
> @@ -643,15 +681,17 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>              break;
>          default:
>              av_log(fmt, AV_LOG_ERROR, "Unsupported pixel format.\n");
> -            return NULL;
> +            return AVERROR(ENOSYS);
>          }
>  
>          if (p->extradata_size)
> -            config = xiph_extradata2config(fmt, p);
> -        else
> +            ret = xiph_extradata2config(fmt, p, &config);
> +        else {
>              av_log(fmt, AV_LOG_ERROR, "Theora configuration info missing\n");
> -        if (!config)
> -            return NULL;
> +            ret = AVERROR_INVALIDDATA;
> +        }
> +        if (ret < 0)
> +            return ret;
>  
>          av_strlcatf(buff, size, "a=rtpmap:%d theora/90000\r\n"
>                                  "a=fmtp:%d delivery-method=inline; "
> @@ -685,7 +725,7 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>              break;
>          default:
>              av_log(fmt, AV_LOG_ERROR, "Unsupported pixel format.\n");
> -            return NULL;
> +            return AVERROR(ENOSYS);
>          }
>  
>          av_strlcatf(buff, size, "a=rtpmap:%d raw/90000\r\n"
> @@ -763,12 +803,12 @@ static char *sdp_write_media_attributes(char *buff, int size, const AVStream *st
>  
>      av_free(config);
>  
> -    return buff;
> +    return 0;
>  }
>  
> -void ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> -                        const char *dest_addr, const char *dest_type,
> -                        int port, int ttl, AVFormatContext *fmt)
> +int ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> +                       const char *dest_addr, const char *dest_type,
> +                       int port, int ttl, AVFormatContext *fmt)
>  {
>      const AVCodecParameters *p = st->codecpar;
>      const char *type;
> @@ -789,7 +829,7 @@ void ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
>          av_strlcatf(buff, size, "b=AS:%"PRId64"\r\n", p->bit_rate / 1000);
>      }
>  
> -    sdp_write_media_attributes(buff, size, st, payload_type, fmt);
> +    return sdp_write_media_attributes(buff, size, st, payload_type, fmt);
>  }
>  
>  int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
> @@ -835,10 +875,13 @@ int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
>                  ttl = 0;
>          }
>          for (j = 0; j < ac[i]->nb_streams; j++) {
> -            ff_sdp_write_media(buf, size, ac[i]->streams[j], index++,
> -                               dst[0] ? dst : NULL, dst_type,
> -                               (port > 0) ? port + j * 2 : 0,
> -                               ttl, ac[i]);
> +            int ret = ff_sdp_write_media(buf, size, ac[i]->streams[j], index++,
> +                                         dst[0] ? dst : NULL, dst_type,
> +                                         (port > 0) ? port + j * 2 : 0,
> +                                         ttl, ac[i]);
> +            if (ret < 0)
> +                return ret;
> +
>              if (port <= 0) {
>                  av_strlcatf(buf, size,
>                                     "a=control:streamid=%d\r\n", i + j);
> @@ -867,9 +910,9 @@ int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
>      return AVERROR(ENOSYS);
>  }
>  
> -void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> -                        const char *dest_addr, const char *dest_type,
> -                        int port, int ttl, AVFormatContext *fmt)
> +int ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> +                       const char *dest_addr, const char *dest_type,
> +                       int port, int ttl, AVFormatContext *fmt)
>  {
>  }
>  #endif
> -- 
> 2.33.0
> 
> _______________________________________________
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> ffmpeg-devel@ffmpeg.org
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> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

On Sat, 4 Dec 2021, Anton Khirnov wrote:

> Return error codes when constructing a stream config fails, rather than
> just disregarding the failure and continuing.
> Propagate the error codes from av_sdp_create().
> ---
> libavformat/internal.h |   7 +-
> libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
> 2 files changed, 120 insertions(+), 76 deletions(-)

> @@ -867,9 +910,9 @@ int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
>     return AVERROR(ENOSYS);
> }
>
> -void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> -                        const char *dest_addr, const char *dest_type,
> -                        int port, int ttl, AVFormatContext *fmt)
> +int ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> +                       const char *dest_addr, const char *dest_type,
> +                       int port, int ttl, AVFormatContext *fmt)
> {
> }
> #endif

This dummy function (which only is compiled if some things are disabled) 
needs a "return 0" too.

Other than that, the patch looks good to me. Thanks!

// Martin

Quoting lance.lmwang@gmail.com (2021-12-05 12:12:54)
> On Sat, Dec 04, 2021 at 06:33:00PM +0100, Anton Khirnov wrote:
> > Return error codes when constructing a stream config fails, rather than
> > just disregarding the failure and continuing.
> > Propagate the error codes from av_sdp_create().
> > ---
> >  libavformat/internal.h |   7 +-
> >  libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
> >  2 files changed, 120 insertions(+), 76 deletions(-)
> > 
> > diff --git a/libavformat/internal.h b/libavformat/internal.h
> > index 528ff7e017..db1d83be17 100644
> > --- a/libavformat/internal.h
> > +++ b/libavformat/internal.h
> > @@ -545,10 +545,11 @@ uint64_t ff_parse_ntp_time(uint64_t ntp_ts);
> >   * @param ttl the time to live of the stream, 0 if not multicast
> >   * @param fmt the AVFormatContext, which might contain options modifying
> >   *            the generated SDP
> > + * @return 0 on success, a negative error code on failure
> >   */
> > -void ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> > -                        const char *dest_addr, const char *dest_type,
> > -                        int port, int ttl, AVFormatContext *fmt);
> > +int ff_sdp_write_media(char *buff, int size, const AVStream *st, int idx,
> > +                       const char *dest_addr, const char *dest_type,
> > +                       int port, int ttl, AVFormatContext *fmt);
> >  
> 
> ff_sdp_write_media() is used by movenc.c also, maybe it's better to add the 
> error check there also.

It didn't appear to be completely trivial, so I judged it to be outside
the scope of this patch.

Quoting Martin Storsjö (2021-12-07 10:14:59)
> On Sat, 4 Dec 2021, Anton Khirnov wrote:
> 
> > Return error codes when constructing a stream config fails, rather than
> > just disregarding the failure and continuing.
> > Propagate the error codes from av_sdp_create().
> > ---
> > libavformat/internal.h |   7 +-
> > libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
> > 2 files changed, 120 insertions(+), 76 deletions(-)
> 
> > @@ -867,9 +910,9 @@ int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
> >     return AVERROR(ENOSYS);
> > }
> >
> > -void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> > -                        const char *dest_addr, const char *dest_type,
> > -                        int port, int ttl, AVFormatContext *fmt)
> > +int ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
> > +                       const char *dest_addr, const char *dest_type,
> > +                       int port, int ttl, AVFormatContext *fmt)
> > {
> > }
> > #endif
> 
> This dummy function (which only is compiled if some things are disabled) 
> needs a "return 0" too.

Should it really be 0 rather than AVERROR(ENOSYS)?

On Tue, 7 Dec 2021, Anton Khirnov wrote:

> Quoting Martin Storsjö (2021-12-07 10:14:59)
>> On Sat, 4 Dec 2021, Anton Khirnov wrote:
>> 
>> > Return error codes when constructing a stream config fails, rather than
>> > just disregarding the failure and continuing.
>> > Propagate the error codes from av_sdp_create().
>> > ---
>> > libavformat/internal.h |   7 +-
>> > libavformat/sdp.c      | 189 +++++++++++++++++++++++++----------------
>> > 2 files changed, 120 insertions(+), 76 deletions(-)
>> 
>> > @@ -867,9 +910,9 @@ int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
>> >     return AVERROR(ENOSYS);
>> > }
>> >
>> > -void ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
>> > -                        const char *dest_addr, const char *dest_type,
>> > -                        int port, int ttl, AVFormatContext *fmt)
>> > +int ff_sdp_write_media(char *buff, int size, AVStream *st, int idx,
>> > +                       const char *dest_addr, const char *dest_type,
>> > +                       int port, int ttl, AVFormatContext *fmt)
>> > {
>> > }
>> > #endif
>> 
>> This dummy function (which only is compiled if some things are disabled) 
>> needs a "return 0" too.
>
> Should it really be 0 rather than AVERROR(ENOSYS)?

Oh right, yeah that'd be more correct indeed.

// Martin